Re: Building own computer step I: What i should look for when selecting a case?
I think at the moment 100-150€ is ~£85-£125, but I can't think of any particular cards in that range. I'll edit this post later with some AMD and Nvidia cards.
Edit - So here are 2 cards from both AMD and Nvidia:
AMD - Firstly, the 6850, it may be a gen old but it beats the 7770 performance wise, and it's inside your budget. Secondly, there's the 6870. It is slightly outside of your budget but it has better performance just in case the 6850 is not enough.
Nvidia - Firstly the 460. It may be 2 gens old but again it offers a lot of power for it's price point, and as a result beats the 550ti (which is also inside your budget). Secondly there is the 560. It is a gen old and also slightly outside your budget, but again offers a little more power in case you want it.
Here's how I would list them (with the best being first);
The reason being that both Nvidia cards OC better than their and counter-parts, and that they both have PhysX (which is only used in a few games, but still a bonus). Other than that the first and second, and the third and fourth, are practically the same - performance-wise.
Once you have chosen you're card you just need to chose a brand (e.g. Gigabyte, MSI, EVGA...). Just look at their reviewsand you'll be fine.