Home audio equipment goes on sale frequently, and when on sale, is up to 50–70% off normal prices. Unless you absolutely must buy right now, it’s worth figuring out what you like AND watching for “deals” online.
I generally like Paradigm, PSB, and other inexpensive speaker-focused companies for speakers; a 5.1 set, or a 5.0 set with separate (optional, potentially unmatched) subwoofer would be where I’d put $150–350. Paradigm Cinema 90 is a pretty good option.
For receiver, an audio-video receiver would be much more convenient than an audio only amp (“integrated amplifier”, or separate pre-amp and power amp; these are more common for audiophile stereo systems than for home theater). Good models include Onkyo, Yamaha, Denon, Pioneer; something in the $250–450 price range is optimal. You want 1080p video switching on HDMI, to allow the PS3 and thus BluRay to display in HDMI on an LCD/Plasma TV with HDMI input, presumably.
You can get an iPod dock for most AVRs, including Onkyo and Denon.
For Pandora playback, I’d go with a Squeezebox, or with a home theater PC (which you may already have). Sonos is the high end option; an Apple Airport Express with airtunes + airfoil would be the low-end option, if you’re a Mac person especially.
Absolutely avoid overpaying on cables; check out monoprice for HDMI cables if you need them.
Assuming you need a TV, 46” LCD 1080p sets are $500–700 on sale for CCFL from last year, or $700–1000 for LED-backlit LCD from now. I’m not sure if that was part of your needs.