Florges - People have said good things about Florges, and gives you an opportunity to try pure Fairy out.
Pangoro - Reception is mixed. Hawlucha is a better fighting type and HM slave
Aegislash - Recommended. Good typing and learns False Swip, gets Swords Dance + Shadow Sneak very early and learns good attacks later. Wait til Level 51 before evolving Doublase.
Aromatisse - Not much to say, more of a bulky all rounder. Probably not the best.
Dragalge - Nice typing, good moves, good special attacker. If you're looking for a Dragon it's a very nice choice.
Tyrantrum - A bit on the slow side and has lots of weaknesses, but easy to make work.
Heliolisk - Recommended. It's the only electric type available, gives you thunder wave, normal typing gives some nice variety of moves, including Surf which is good coverage and leaves a HM slot for an actual water type if you get one.
Gourgeist - Nice bunch of utilities and decent typing. Can't go wrong.
Avalugg - Pure Ice types suck ass, especially when they're slow and "bulky". That being said, in-game is the only time to use it so if you really like him then go ahead.
Noivern - Solid special attacker. Good choice for a dedicated flier.
I wouldn't discount the other starters either, no doubt if you find one of them is a perfect fit for your team then somebody can trade you them. Some mons come pretty late too so if you want them you should get people to trade you them.
Really what matters is personal choice.
