Yanmega

Personally, I'm not a huge fan of bugs (especially not unnaturally large dragonflies), but for some reason I was thinking about Yanmega the other day. After seeing its not-too-shabby HP stat and that it can learn Roost, I decided to concoct a stalling set =)

Yanmega @ Leftovers
Speed Boost
Calm Nature
EV's: 220 HP/8 Sp Attack/44 Spd/140 Defence/98 Sp Defence

~ Toxic
~ Roost
~ Air Slash
~ HP Ground

Simple enough, I suppose. Toxic to start things off (hopefully while the opponent sets up, expecting a Protect), and Roost away! Speed Boost makes you scarily fast so you won't need to worry too much about getting attacked before you can heal up again. I guess there are priority moves to think about but Yanmega has that covered since it's not as frail as you might think. Yanmega has enough defence to withstand Life Orbed Scizor Bullet Punches, Metagross Meteor Mashes and Azumarill Aqua Jets so it can hang around for a while if you want it to. As for the other moves, Air Slash, as well as being a great STAB move, can flinch, racking you up another round of poison without Yanmega taking a point of damage. HP Ground is for Steel types who would otherwise quite happily wall you.

The HP EV's give max Lefties recovery, which mean some more EV's can go into the rather generous helping of Special Defence (a stat that really lets Yanmega down). The Defence stat is also given some EV's for better all-round stability. Max speed definately isn't a neccessity but a bit of investment never hurts. Also a smattering of Special Attack give attacks a bit more bite.

I think it looks pretty good, but you might consider utilizing 224 HP instead, so Stealth Rock can be switched in on an extra time IF absolutely necessary. It's a situational thing to worry about, but with SR on every offensive team out there it wouldn't hurt. Nice set though, I like it