TIM is an old and a great puzzle game. Braid is a platform adventure game with really nice graphics. Machinarium is a bang-on adventure and I just finished it, great puzzles in it I must say.
I loved The Incredible Machine soundtrack back in the day. I got a loan of the CD from a friend (before I had a PC) and copied it to cassette. Yeah, you heard me - cassette, bitches
Point and click adventures are usually a safe bet because they're always low-resource. I love the King's Quest games. KQIV to VII are all great. Not so keen on the old VGA ones though.
Find the DOS remakes of Dizzy games too, they age brilliantly. Prince of the Yolk Folk is still my favourite, although Spellbound Dizzy is amazingly complex and fun too.
From older racing games definitely Toca 2, V-Rally 2, Driver 1, or CMR 2.0 or NFS5, as mentioned before. See gameplay videos on youtube, I think those games are still the best. And no, it's not nostalgy speaking from me. Well, maybe a little bit.
OK! Now I'm here with some inet so I can reply. Not enough bandwith to get more games but still will check this list so when I'm back I can gear my notebook a bit more.
Must say that mafia was a great idea, started playing it and now I'm really hooked. Also have NfS5 to play around, and Crimson Skies is IMO a must have!
Oh just keep on playing.. and don't quit if you get stuck somewhere.. I was an i*iot and was stuck on one part, and had a break for 2, 3 months cause of that, and it wasn't even something that hard to figure out.. God i can't f*ckin wait for Mafia II.