I have never played diablo and don't really play alot of rpg's ...but this seems like a good game to get into this genre. 
 
Is this a good game to start on?  

Torchlight is a great game, try out the demo if you're still unsure.

" Torchlight is a great game, try out the demo if you're still unsure. "

Diablo is really old. I suggest the newer games, Torchlight looks good.

I still prefer Diablo II overall, but this is a great game to start with if you're only interested in single-player.

Diablo II is still very playable (the original Diablo less so -- though I personally don't have much trouble going back to that either), but this is actually my favorite Diablo clone and serves as an excellent introduction to the genre as it has more in common with the original Diablo than Diablo II, so I say go for it. You might wanna check out Darkstone as well -- it's basically a hybrid of the original Diablo and a Zelda game and also one of my favorites.
 
Oh, and if you do end up picking up Torchlight and have any prior experience playing PC games, you'll probably wanna pick Hard Mode and not Normal  -- trust me.

Torchlight is a good place to start if you are interested in these sorts of games. Personally, Torchlight is my favorite one of these hack n' slash dungeon crawlers. I like it way more than Diablo II. If you are unsure you should check out the demo and give it a whirl. If you like it enough to buy it you don't have to worry about starting over since your character and everything from the demo transfers over to the full game.

This game is almost exactly like Diablo II with a little bit of WoW mixed in (wtf fishing).  I'm really enjoying it so far, but then D2 was something I could play almost any time.  It's nice to have D2 that's not D2.

If you like Torchlight, you might want to check out Titan Quest, too.  It's like Diablo but better looking since it's newer and it's full of Greek mythology instead of standard fantasy beasties.

Absolutely I'm on level 20 right now I recommend it whole heartedly.

Torchlight is a more gentle game for those who are new to the genre. And Diablo are more raw. So start up with Torchlight, and you should definitely try Diablo 2 out later.