Is it worth buying a Xbox 360 controller?/ Good games with controller port

Because I really want to play Dark Souls, Batmans Arkhams, SMB and let my son play Toki Tori 2+.

Or do I buy a $10-ish dollar controller?

Thanks in advance.

Edit1: Thanks a lot for all of the comments. I bought a wired X360 controller. The experience playin' Dark Souls and Batman Arkham City was awesome! Which games would you recommend to acquire having this awesome controller including DS and Batman?