For 2.1, you have a lot more options. If you went with 2.1 initially, you could still get a 5.1 receiver and leave yourself the option to complete the system at a later date.
Listen to his advice. It's golden.
Most real audio enthusiasts will tell you to get quality, and get what you can afford now, rather than getting 5.1 or 7.1 and getting crap.
Start with a good pair of stereo speakers. That's your foundation. If you're going predominantly movies, you'll want to get a sub as soon as possible. Don't skimp on the sub, but you don't have to go crazy, either. There are good solutions under $300, if you're trying to tightly control cost.
Once your 2.1 is in place, you'll most likely want to add surround. There are opposing views on this - some people will point out that dialogue is 80% of your audio in movies, so you need to get a center right away. For my taste, I can live with a phantom center better than a lack of surround, so I'd get the surrounds (go to 5.1, not 7.1. You may eventually want to be at 7.1, but those last two rears are the least important part of your system...and a good 5.1 sounds much better than a haphazard 7.1).
When it comes to matching the speakers, the most important match is between the center and the fronts. You want a consistent sound across the front stage. Matching the surrounds to the fronts is nice, particularly if you play any multichannel music or multichannel concerts, but it is not as important as matching the front stage (once again, opinions vary on how important). The sub is the one part that doesn't need to match tonally at all. I didn't even stay with the same manufacturer on the sub - and you probably won't, since few companies are great at both, particularly in the value lines.
