I used to play jungle with a handful of champions (Jarvan, Udyr, Volibear, Xin, Warwick and some others) but have since focused on just two, Jarvan and Xin. Their mechanics are similar so if one gets banned or picked I have the other. Thankfully neither get banned or picked that often at the level I currently play at.
I also play support a lot now too and have focused on playing two as well, Sona and Leona. They play differently from each other but are so strong in lane and in team fights. They also have the benefit of not being banned too often (or picked for some reason)
The Season 4 changes to gold flow for both junglers and supports makes both roles a lot more impactful. It's possible to build big items in both roles and you can really help carry your team.
For example as a Jungler I used to only get tanky items like Spirit of the Ancient Golem and then a Randiun's Omen and that's about it. Now I have enough gold to add a big damage item like Trinity Force or Black Cleaver so I can do more damage in addition to the massive amount of crowd control in both Jarvan or Xin's kit.
As support I can get more than Locket of the Iron Solari and wards. With Leona I can often pick up a Sunfire Cape or Randiun's Omen and with Sona you can add some AP items to help boost your heals and power chords. The unfortunate thing is the 3 ward limit as I can't just light up the whole map now. Not sure if that is worth the extra items but time will tell (and hopefully teaches the other 4 players to ward too).
Sadly I still don't practice the other roles so I'm pretty bad at them. Though that's mostly because I can't last hit very well (but I am getting better!) and that puts me behind my opponent. Oddly enough I am very good at trading with my opponents and I can usually secure a kill on them before they get one on me. Unfortunately I have a hard time translating that advantage into a win for my team.
Oh well, things to work on for Season 4.
On another note, I think I've spent more on LoL skins in the past year than I have on Warhammer in the past decade. Can't decide if that means my hobbies have just changed or Warhammer has gotten to the point where it's prices are too high and I'd rather spend that money on digital goods which are individually much much cheaper. I've almost decided to drop the hobby altogether and get rid of my stuff. That might mean a name change for my blog as I will have no Deathwing anymore.