Help me choose my lipo!

What's it going into?

First, the flightpower packs are going to be about the best that money can buy. The maxamps packs are good for the money. Of the maxamps packs, the best choices would be either the 8Ah or 5Ah packs.

Since you've listed a bunch of 2S packs, I'll guess that's what you need. For a 1/10 scale perhaps? If so, I'd go for the track power 4900 pack. Super pack. Just be sure to get the balancer. You probably won't need it with the trackpowers, but it's always better to be safe than sorry.

If you do decide to consider something else, be sure to check the physical dimensions on the packs that you are looking at. The "flight" power packs are meant for flying vehicles and are sized accordingly; although many have gone for the 4900mAh packs for land based vehicles.