Nothing wrong with starting out with an HTiB. As long as you are happy with it, that's the most important thing. Upgrading piece by piece is a good way to end up with a little bit better of a system down the road as you progress, and that's what most people I've run across end up doing. That's what I did too. Save up, buy one or two nice new pieces, then save up and get a few more as budget allows.
I just sold my surround speakers tonight, so I will be almost going back to stereo until the new ones arrive

Nothing wrong with stereo either, I listen to mostly music, and I actually prefer stereo most of the time.