Speaking as a console gamer, with a pretty limited experience when it comes to PC games, Splinter Cell is pretty obviously designed to be played with a controller. It's a pretty slow paced game so far, so it hasn't been a huge issue, but I'm thinking that I'll invest in one of those 360 controllers for the PC.
I've already picked up the first Half Life, but haven't put too much time into it yet. I'll have to check out Deus Ex.
The PC games I've already got kicking around prior to this were GTA, GTA2, GTA: London, GTA3, Driver, and Warcraft II: Battle.net Edition.
I played a little bit of Tiberian Sun back in the day, so I might check out those, and the Total War games too. Which Total War game would you reccomend the most?
I really want to play Grim Fandango, but it's not on Steam. Know any legal way to get ahold of it?
Yeah I've only ever played Splinter Cell on Xbox/360 and I couldn't imagine it without analogue sticks for creeping/movement. Then again I had a friend who had it on PC and said using the mouse-wheel to creep/open doors etc was okay, but I would still try to get a wired 360 pad which you can then use on PC.
I think you'll really like Half-Life when you get a chance to get into it. Try to set aside some time to sink your teeth into it, it's really a great game. The expansion/spin-off of Half-Life: Opposing Force is really good too if you like the first one and want more of the same when you're done!
For Total War games, they are all really good. It's sometimes hard to go back to an older one since you might miss some new features, but if you're just starting out then I think you might as well choose whichever era you are interested most in. I haven't played Shogun or Medieval 1 yet, but from the newer releases (That will definitely work on your PC) you can go with Rome Total War, Medieval 2 Total War and Empires Total War.
Come to think of it, Rome or Medieval 2 might be best, since they are a bit easier to learn than Empires IMO. So if you like Legions and Phalanxes go with Rome, if you like Knights and Longbows, go with Medieval
Finally, for Grim Fandango, I know that LucasArts recently did a re-release of many of their games optimised for new computers. They come on DVD and can be run without installations I believe.
Here this is the version I meant:
http://cgi.ebay.com.au/GRIM-FANDANGO-PC ... 255a4bbdd7Althoug thats quite expensive, I only paid $10 Australian for the same copy a few years back. Check out your local shops, they might have a copy, if not take a look on eBay/Amazon etc for some more reasonable priced copies. It's well worth tracking down though, it's a really fantastic game, and only on PC.