Starter HT plans... critiques?

[skygreenleopard]

Hey guys,

After years of using a 2.1 PC speaker system on my TVs by plugging them into a headphone port (actually works quite well sound-wise, these old Altec Lansings just won't give up!), I'm thinking of starting a quality budget HT.

Fry's has some Polk R50s for $60 right now - I've confirmed my store has them in stock. I'm considering pairing them with an Onkyo 605 I'll buy used. I've got a PS3 and a Samsung LN40A550 40" LCD to hook up.

I'm thinking of starting with just the Polks and the receiver for now, then adding a center and sub next. My questions are:

• 1) Is this a good basis for a first-time system, or will I want to get rid of those R50s before adding a center and sub?
• 2) If the speakers are passable with a center or sub, what do you all recommend as some I might want to keep for a couple of years? The Polk CS's look like keepers, and feel free to throw out any anecdotal experiences with subs you may have had.
• 3) When I (eventually add surrounds), would it be advisable to move the R50s back and upgrade at the front, keep the R50s and buy a new pair (maybe more R50s, or some bookshelves, or something else), or would the R50s be best sold and upgrade all 4 L/R speakers at once?

Thanks for any help, guys. Even if you don't have any direct advice, any experiences relating to a starter setup are welcome.