Inspired by two topics here I decided to do my own and the reason is: I actually have most of the "best selling" puzzles, and I do not have any "rare" one because I just started this hobby last year.
So, basically, not much for rarity I look for a puzzle, but actually for its beauty or even "how fun" I will have with it.
With that in mind, I could gather the following collection:

Rubik's 3x3x3
Dayan GuHong 3x3x3
Haiyan's Memory 3x3x3
Ghost Hand 2x2x2
Maru 4x4x4
Dayan+Mf8 4x4x4
Ghost Hand 5x5x5
V-cube 5
Meffert's Skewb
Meffert's Pyraminx
Mf8 Megaminx
Hungarian Supernova
Fisher's Cube
Mirror's Block
Gear Cube
Gear Cube with Fisher's Stickers
Square-1
Rex Cube
Rainbow Cube
Face Turning Octahedron
Axis Cube

Arriving: Tuttminx, Prof Pyraminx, Mosaic Cube, Helicopter Cube and Maze Stickers.

What I want to know is: aby cubes that I might find fun or beautiful to purchase?
Toping my list are the Volcano and the master Skewb.
I do prefer mass product puzzles, as usually I just can't afford to pay more than 100 dollars, so please, any suggestions?

$100? Get a Shapeways puzzle then, maybe an Edge Turning Octahedron, Pentultimate, 2x3x4, Unbandaged Helicopter Cube or a Star Puzzle With a Twist.

I'd recommend a 2x3x3, lots of fun to solve!
Maybe a masterball? Or a dayan gem?
You could get ALL of those and still have change out of $100!
(what i mean there is that $100 will buy you a lot of puzzlement!)

Sebuver, taxes in my country are... 100%, including in the calculations the shipping price.
When a package comes from China (for example), because of the large quantity, it's high the chances of not being taxed, but, when a package comes from the UK, well, it's almost a 100% chance that I will pay an absurd amount of taxes. XD

In fact, the puzzle that I want the most is the Curvy Copter, but... imagine paying 300 dollars! Plus shipping and 100% of the shipping costs only in taxes!

For once, I purchased parts for my Gear Cube and I paid, total, about 80 dollars just to discover that the Gear Cube Extreme would be also mass produced! That's why it'll be quite difficult, for me, to buy something other than mass produced puzzles!

Shapeways is in America, not England. There must be a lot of stuff imported from America, right? Oh, and shipping is free from Shapeways.

America? I always thought it was based in Holland.

It was, but then they moved to New York a few months ago.

The UPS thing is a killer for me: fast, but always pays all the taxes.

As for new ideas, I recently bought the Master Skewb (seems very fun to solve, and it's beautiful... at least for my taste).
And I think I could come up with a little list, so, if people can add a little comment to these puzles, please, do:

Volcano
Pyraminx Crystal
Flowerminx
Skewb Ultimate
Pyramorphinx (I don't really know if I get Fisher's or the pillowed one)
Sbramble Cube
Void Cube
Latch Cube
Gigaminx
Super 3x3x3
v-6
v-7

Vulcano:
If collecting is your interest, this is a very cool puzzle. However, from a solving standpoint, it does not turn very well at all. It is also not very aesthetically pleasing because the stickers are all off place.


Pyraminx Crystal:
The original is a real beauty if you get one. Do not settle for a KO. They are just gross. Good puzzle to have.


Flowerminx:
I personally wouldn't make this a high priority puzzle, but from what I have seen, it is a cool puzzle to doddle around with.


Skewb Ultimate:
Lots of fun! If you liked the skewb, you will probably like this. There are lots of choices to suit your sticker and color taste as well.


Pyramorphinx (I don't really know if I get Fisher's or the pillowed one)
-Not knowledgeable to comment-


Scramble Cube
-Same as above-


Void Cube
This is fun to have sometimes, but not if you are looking for a truly unique solving challenge.


Latch Cube
-N/A-


Gigaminx
-N/A-


Super 3x3x3


v-6, v-7
Getting a V-cube set is a really good idea. Vcube puzzles are fun, unique, goo quality, good looking, and just in general nice to have. Even though it's a wink above 100 dollars, I would suggest getting a full set of 2a, 2b, 5, 6, 7 in whatever color you prefer.

I'll comment on these puzzles as well.

Vulcano - I have two versions, one black, one white. The white one turns wonderfully, very smooth, never catches or pops, and is amazing! The black I have not adjusted yet. Very fun puzzle, fairly easy to solve, I would get one before it's too late.

Pyraminx Crystal - I do not own one, but I am dying to obtain one. From what I have heard this is another must have puzzle.

Flowerminx - Once again I do not own one, but I have considered getting one to add to the dodecahedron collection.

Skewb Ultimate - I was never really attracted to this puzzle, so I do not own one and cannot vouch for or against it.

Pyramorphinx - A nice shape mod, not really a new solving challenge from what you have, so I would put this as low priority.

Scramble Cube - I do not own one.

Void Cube - Solving is the same as the 3x3 except for the parity, so I decided not to get one (can always just remove center stickers from a 3x3 and get the same thing)

Latch Cube - A must have! An exceptional challenge, in my opinion, one that took a lot of patience to solve. Get one before it's too late!

Gigaminx - Another fun puzzle, I would buy one of the Mf8 ones as they are supposedly much better than the C4U.

Super 3x3x3 - Personally I prefer new and different mechanisms as opposed to sticker modifications, but it is personal preference, I would get another puzzle before this.

V-6 and V-7 - I own a V-6 and it is one of the most high quality cubes I have. Soon I will be purchasing the entire V-cube set (with the exception of the 3x3 and 4x4 which haven't been released at this time) due to their great reputation and quality.

Hope this helps!

Chris

Thank you for the responses!

The only puzzle that I'm a little bit afreid to buy is the v-cube 6. It seems that the majority of the people do the memyselfandpi mod, and I'm too afraid of buying a pricey product just to modify it. But toping my list are the Crystal Pyraminx, Vulcano and a latch Cube!

Here are my thoughts on what to get if you would like to get into Speedcubing:

V-Cube 2x2x2 (when I tried it, it wasn't perfect but I knew instantly that with break in it could be phenomenal. Right out of the box that thing is a beast)
Guhong 3x3x3 (This is, I must say, the fastest puzzle I've ever played with- you'd be hard-pressed to disagree)
X-Cube 4x4x4 (it's expensive, and it needs break-in, but it's well worth the price, owners say)
V-Cube 5x5x5 (with break in this thing is the best brand 5x5x5 ever made)
Meffert's Megaminx (again, break in before lubricating and this is unstoppable)

Is there an adjustable Pyraminx? Mine is loose on 3 corners and very tight on the 4th, making it very unenjoyable to play with. Similar problems existed in about 30% of those I played with.

Pyraminx crystals are amazing! If you have the money, it should be the first thing you buy. Also shapeways is in both New York and the Netherlands.

I myself am not a speedcuber, so I have always loved trhe V-6 cube. I can understand why the speedcubers do not like it clicking and catching every turn, but personally I like it for it makes the cube feel very stable. But of course, to each his own

Chris