Re: Onkyo 5.1
It's hard to build an entire 5.1 system including the AVR for $269.- so there isn't really an alternative to such systems as the onkyo one. Onkyo is a quality brand, that's for sure, they do make good receivers, I use one myself and I'm glad with it. I haven't heard one of their 5.1 systems yet, but I'm sure they are worth their money, you should listen to the system before you buy it never the less.
You could also think about buying an AVR (like an Onkyo SR505) and go stereo first. A good stereo set will likely sound better than a cheap 5.1 system anyway and with such an AVR you can upgrade anytime you want to, though this will be more expensive.
Audiatur et altera pars!