First off, the battery is good for 300+ shots with flash. And most of us that use DSLRs carry at least one spare battery. I have a 350D (also known in the USA as the XT) with external grip which can use 1 or 2 lithiums or 6XAAs. And grips are available for all the Rebel series Canons.
Second, it is a fabulous camera. But if all you want is beam shots, it's using thermonuclear weapons to swat flies. That is a very serious, semi-pro level or advanced amateur level camera. And once you get into the DSLR range, well, say goodbye to your wallet. Lenses, filters, exernal flash, tripods, and then upgraditis to a 40D or maybe even a 5D or something in the 1D series.
As I said, I have a 350D, 2 updates earlier, a K2 35mm film SLR, and an S5IS compact. 3 lenses to fit the 350D, 2 for the K2 that also fit the 350D, 430EX flash, Pelican case, lots of filters and other accesories. And all I wanted to do was take vacation pictures.
Just remember that SLRs are VERY addictive.
JMNSHO &, of course, YMMV