I see in today's front page that Canon is cracking down on counterfit Canon products. I did not realize this was even an issue. What counterfit things are out there? On a second thought... are third party batteries as good as Canon batteries?
So far in my experience, yes they are as good, provided you buy them from a reputable seller. I have purchased aftermarket batteries for my Canon Xti, T1i, 40D and now 7D. I have never had an issue with them except one battery that wouldn't take a charge and the seller sent me a replacement battery within a couple of days, no questions asked.
The current set I have for my 7D are made by a company called "Wasabi Power" and I bought 2 batteries (Canon LP-E6), holders, an A/C charger and an adapter for 12V DC automotive power for $29.99 (plus shipping) from Amazon.
They company shipped them very fast (I got them in a couple of days) and they have been fantastic. They work perfectly with the Canon chargers and my 7D. They hold power just as long as my Canon batteries do.
I have photography friends that swear up and down that aftermarket batteries suck and can short out your camera. Well, I have never actually met anyone who has had that happen and I have bought dozen of aftermarket batteries with great luck. I will keep buying them. Any words of advice? Take your time and look for an honest seller, that way your chances of avoiding problems are minimized.