Trine 2 is an excellent choice! I bought it during the winter sale last year, but it's definitely a steal at the current price.
Valve is definitely making my wallet lighter as well, I already got GRAW2 and the Half-life collection, but I still got my eye on some other games as well! I promised myself not to exceed 50 euros of spending though, haha.

Hiya Cheeze, enjoying the Summer Sale?
Answering your question on my profile: no, I don't actually have exams or whatnot, it's just writing a thesis and handing it in. Hopefully finished next week, so I can play some games again.