Will you buy an RPG just by the fact that it is an RPG?
Possibly, If it looks fun.
How do you decide to buy an RPG?reviews,word of mouth, forums?
Normally by word of mouth, but reviews do help, as well as the big words 'on sale'.
Do you cheat/ use hacks/editors?
I don't cheat, but I sure the hell will play around with the editor just because I like creating my own stuff. Again, I mean the 'built in' editors, not like external hex editors and such.
Do you use walk throughs?
Depends, now a days you can just look on youtube and someone will have the solution to your problem.
Do you download the latest patch before you start a game?
I probably wouldn't have known that the game even had a patch unless there was a built in patching utility. This is an exception for Neverwinter Nights as you have to download the critical rebuild externally.
Do you prefer single character or party?
It depends, I like party based combat if it works well and is cohesive. But even in that case, I normally would take it upon myself to figure out a way to solo the game, just for the extra challenge. Also, when playing party based games, I like games with a lot of interaction abilities between party members. Having them simply exist sucks.
Do you prefer single player or multipalyer?
I prefer all the player
Generally I'll even play multiplayer (mmo) games by myself, but it is very very fun and interesting to play with friends. I'll prefer being able to play with friends over any other type of game. But single player games are great as well, as long as there's a lot of replay-value, beyond just 'different races and classes'.