I recently purchased new lipos after running thunderpower packs fort he last 3 yrs. and the best bang for your buck is the SMC 7200 packs. They were at the bottom of my list but @ $65 per pack they are a steal and great performing packs. The others were revtech 7150 and trinity extreme sting 7200. In that order with the trinity pack performing the best. You can pick up 2 SMC packs for less than 1 trinity pack. Depends on your budget.
http://www.smc-racing.net/index.php?...product_id=115
(Don't worry about the pre order. I order edit he same wayang d they were at my house within the week)