For starting batteries I would definitely go with the discounted Duracell brand from Batteries n Bulbs/Batteries Plus. They pretty much always have a discount going on their site. I shop online and purchase them for store pickup, drive right over to the store and get them a few minutes later. I'm 5 minutes from a store though. All but their cheapest batteries are East Penn/DEKA and are a really good battery for the money.
@unreng - "We have a 4DL as the house battery in the van, but haven't been able to use it since the van's in the shop, so can't provide feedback."
- You'll be pleased with a 4d when you get up and running. Most late model SMB's have one 4d. If you have any solar at all, even a 100w panel, all the better. The 4d is plenty for most average camper van's power needs.