since the captain thread seem to be doing fairly well so far (whee, lack of flame wars). let's talk about the VCs =D
there's really not as many to list, considering you either never see their ability, or they got ownd way too quickly.
renji: he's probably the strongest VC, and probably the only one that has attained ban kai. he's quickly nearing the level of a captain. his raw strength and endurance are crazy; however, his kidou power is weak/non-existant
yachiru: although you never really get to see her fight, just her aura was enough to scare off a special-ops dude. i don't think she's stronger than renji, since she thinks that knowing your sword is "cheap" (eg 2v1). i doubt we'll ever see her fight... yachiru fighting would be... so wrong oO;;
rangiku/kira: you never really see the end of this fight... personally, i think they're rather on par with each other.
hinamori: her kidou abilities are strong, but she is not the fighting type. period.
iba: however, i think hinamori is probably strong than iba, who - from the looks of it - split even with ikkaku. and had to transfer to another division just to become a VC.
shuuhei: geez... for a "prodigy", losing to a 5th seat?
1st VC, oomaeda, isane, kaien: n/a. got pwnd too fast.
nanao, nemu: n/a. you don't really see these girls fight