It really depends on your personal tastes and budget.
IMHO, I believe you will be extremely happy with a 50mm lens of some sort. The Canon 50mm 1.8 is pretty good and produces great images. It's also cheap, both in price and build quality. The 1.4 version is of higher build quality, but it's 3x the price of the 1.8. You should buy one of these lenses. The wide aperture is a killer app, giving you a lot of versatility in low light.
For macro, get automatic extension tubes. Kenko brand ones are pretty good and are readily available for around $100. Don't bother with Canon ones, it's not worth the money considering they're just empty tubes. You can use this with the 50mm and get some serious close up images.
As for an all around general lens, I'd personally hang onto the kit lens that comes with the camera for a while. Once you get used to that and understand its weaknesses, you will know what you want in the next lens you buy.
These three items can go a very very long way.
Congrats on the new camera!