I suck at G&W. Wolf or Sonic would be my best, highest tier character I think. I also enjoy playing as Oldmanondorf :D. Of course, Link is the always the best choice, so I usually just play him. haha.
I would imagine Marth would be a fairly good choice as a second since he's a good character who depends on good spacing, and if we're maining Link, we need to have good spacing anyway. Snake probably wouldn't have quite as steep a learning curve either.
There's always that nice, shiny Meta Knight sitting pretty at number one, too...
You could always try just playing as Random until you find someone you kinda like, enjoy playing, or just seem to click with, and try picking them up. Honestly, that's how I picked up Link in the first place, haha; I always liked Link as a character but didn't like him much in Melee and never tried him in Brawl. Then I randomed him like 3 times in a row and kinda liked him, and figured, eh, I'm maining the (at the time) worst character, Captain Falcon, anyway; why not swap to a character I like a lot more if I'm gonna be using a bottom tier character anyway, haha.