There's a ton of gamepads you can buy, and you can hook up a 360 controller too. Just about every game should have controller support, but if it doesn't there's more than likely a mod or patch you can download and run to enable controller support. Might not be possible for older games but you never know.
Il have to look into that, not that I think my rinky dink $200 laptop could handle a graphics intensive game, but it would be nice to try some older games see how it fares.
As to the original topic. Ive never played Darksouls so I cant give my opinion on that(Judging from other peoples posts though I might have to check it out as its almost unanimous that everyone thinks DS is better than Diablo 3) but Ive been playing Diablo 3 on 360 since it came out so heres my take on it:
Its a fun game to pass the time if your into the level/grind/loot/hack and slash/kill and plunder type of game. It is not rocket science. It will not challenge you to any great degree( compared to say Ninja Gaiden 2 which I consider to be one of the most challenging games ever made) Im on my 2nd playthough in nightmare mode with a level 40 Wizard and thus far I steamroll over anything that gets in my way. It is very fun to play online with your buddies and a headset. The online is superb and Ive never noticed any kind of slowdown/delay/lag. The story is meh, but engaging enough to keep you going. It is very linear. You aren't going to get sidetracked doing endless side quests that lead nowhere. There is always a yellow arrow on the map pointing to where you should be going. Like I said, its not brain surgery.
The main focus of the game is to constantly keep upgrading your characters level/stats/gear. The graphics are decent, but not mindblowing. The characters have a limited amount of customability. Mostly what gear you use and what powers you decide to use. You cant customize things like how far their eyes are apart from each other or what theyre skin tone is, and that's fine by me. I find that level of customizing to be tedious and take a long time for no reason.
Diablo 3 is an easy game to jump into and start hacking away. Its fun, but not challenging. Somewhat repetitive, but not boring. The whole point is the process of leveling your character to ever more soaring heights of overpoweredness. The fact that you do this by basically doing the same thing over and over(I.E. killing swarms of monsters) is secondary.