Since you like RPGs:

Tales of Heroes: Trails in the Sky
Final Fantasy 3, 4, 4: The After Years, 7, 8 (heard the audio sucks though)
The Last Remnant
On The Rain Slick Precipice of Darkness series
To The Moon (Made with RPG Maker)
The Witcher series
Valkyria Chronicles

Amazing non-RPG games:

The Stanley Parable
Gone Home
Dear Esther
The Vanishing of Ethan Carter
The Talos Principle
Psychonauts

And like others have said already, wait for sales and bundles. Sure they're technically destroying the PC gaming market, but you're getting deals bro. Deals!

StarCraft 2
Diablo III

That's weird. I'm in Spain and the link works for me. And going directly to Steam I can find Anno 1404, the Venice expansion and the Gold edition.

Maybe it's blocked in the UK for some unknown reason...

Going by this thread http://steamcommunity.com/app/33210/discussions/0/617320628230976504/?insideModal=1 it seems Anno 1404 (called Dawn of Discovery/DoD in USA) was available for UK at least until the end of last year. For some reason Ubisoft seems to pull Anno games from time to time for selected countries. Reason unknown.

I think they mean to push more software throug uPlay alone, they want a bigger piece of the income.

The steam sales start on 11 June that is pretty soon I would wait to buy some stuff because their will be for sure something you want.

Other than RPG: Thief I, II and III, probably the best stealth series ever, Myth I and II (avoid that crappy Myth III), two masterpiece RTS' (or more properly real-time tactics, not strategy) that can appeal also to not fans of RTS.
RPG: Witcher series, and if you like that kind of RPG, also Gothic I and II (play Gothic games first in this case, otherwise their graphics could look oldish compared to the newer Witcher). Planescape:Torment for an isometric RPG very different from usual. If you find it at a low price, Temple of Elemental Evil may be not the deeper RPG, but it poses nice, challenging tactical problems, you'll often have to fight hordes of enemies with a small party.
Throne of Darkness is an RPG with Diablo II engine, but feudal Japan settings, initially its gameplay can seem awkward, but it becomes smooth when you get used to it (it doesn't take too much, really), and then the game becomes really good, with very nice graphics not just for their own sake, but that serve well the whole game and the player's immersion.

It's Ubisoft, who the hell knows what they are up to.

Besides being a**holes, of course.

The Last Remnant

Yeah I figured they'd pulled some stupid shit, this is why Ubisoft are at the bottom of my shit list of corps I don't care/won't support, I hardly bother with Uplay and don't see a reason to bother with it since any Ubi bought game on Steam requires Uplay and then Uplay requires me to download the game even though it;s on my HDD, tried everything in the book but Uplay stamps it's foot down like a child demanding I download the game a second time, if I delete the original it fucks everything up, dunno why but that's Ubisoft for you, Origin gets more love from me than Uplay ever will.