Were it not for some serious (SERIOUS) shipping issues with orders originating from Hong Kong from merchants including but not limited to HobbyKing - you would be on the money.
The bit about price is basically for C ratings, if there is a believeable review of the particular battery (like on ES here) and results have been good... they will get recommended. Under normal circumstances I would say go with Turnigy or Zippy 20C or better (go as high in C as you can afford, those will hold a higher voltage longer under heavier loads and with less internal resistance they will stay cooler... that's actually how they deliver better discharge rates)...
Right now we are all (and hundreds of normal RC hobbiests) waiting (I'm turning blue man) for Hobby King to come through with our orders... there has been lots of "poor shipping / business" practice going on in the past few weeks... you can find the threads here and on Hobby King's own forums so I won't go into detail...
Personally if your just jumping in, wait a week or two... see how these things sort out.
Were also looking into other vendors here in the US like HobbyPartz as alternatives for the near term (hopefully that's all it will be) and should have viable tech information / review up tommorow night with regards to their packs... mine are due tommorow via UPS and I will report as soon as possible if they are a viable alternative to Hobby King for now.
Only downside with HobbyPartz is their stock is quite limited at the moment, there are other solutions in the sauce pan (thought, partial planning stages) in case this bit with Hobby King is persistent (permanent).
Sorry to be the one to break it to you, Lipo rocks on eBikes and this really sucks for all of us!
2010 Dahon Jack - GNG v1 - LYEN 6FET - 20/40A - 18S2P10AH - Nom:66.6v,1332w
2004 Hard Rock Pro Disc - Recumpence ms eDrive v4 - Astro 3220 4T - 12S2P16AH - HV110 - Left Side Drive - Gearing: 38mph
Nominal Peak Power @ 60 seconds: 5328 watts - Maximum Power: 49.8v, 120A, 5872w
2010 Downtube 8FH - Stock GNG v1 Stock Controller - EB809XC - 12-16S
2012 Downtube Nova 7spd - Stock GNG v2 - 12S2P10AH - EB809 - 12S-16S - 20A/30A,Nom VCC: 44.4, 888w