For about $20 to $25 from Hobby King (or is it called Hobby City now or vise versa?) you can get the Accucel 6 computerized charger. It's very popular among the RC crowd because of all the features it has and ability to charge many different battery types. Feature wise you can't really find a charger for less than say about $125 to compare to it. Only problem is it does require a 12V power source, so either buy one off their site for about $6, run it off your cigarette lighter in the car, or hook it up to a 12V battery from a car or boat or something. Warning though, this charger is not for the novice. You can set many different things on it such as amp rate and so on. It also doesn't come with the manual you have to print it out from their site. There are also excellent long threads on this charger (look on RCgroups.com) for people to help understand how to use it.
I use it to charge my lipos for my GT and my planes, as well as my nimhs and nicads. You can charge your GT battery pack with it but you can't do it through the charging port as there is a charging circuit in there. Instead you've got to hook it up to the two main battery leads on the pack that make contact with the detector when plugged in. The charger will tell you if you have the polarity reversed and comes with alligator clips to hook it up to them.
I simply love this charger, and believe me I've own a lot of chargers over the years. Not for everybody, though. It's not hard to understand the settings on it but it requires a little reading on the web and such.
The beauty is for your GT 1000ma nimh pack you can charge it slow at say 100ma for a 10 hour charge time like you should whenever possible, or if in a rush you can charge it at 1 amp and have a dead pack ready in an hour, though I don't like pushing packs that fast too often as it can shorten the battery life a bit. On the other hand, I know guys who fast charge their packs all the time and probably won't have any issues for years.