Greetings from south of the river

I presume you're up at the U. I will say I've had great luck with finding used mid-fi gear here in the cities on craigslist. All of the gear in my sig with the exception of the display and the receiver (ebay) were all purchased used, locally.
Personally, part of me thinks you'd be better off buying the best used speakers you possibly could, whether they be bookshelves or floorstanders is probably dependent upon whats available and what you decide you'd like to move around. Given that eventually you're going to want to turn your music listening bedroom system into a theater system later, seems like you won't be out anything by investing in better speakers now and buying a receiver with the HDMI bells and whistles later. The cheapy receiver you buy now can continue life as a bedroom/garage receiver eventually.
Last I checked there were multiple sellers in the cities area unloading Paradigm and B&W (bowers & wilkins) gear for reasonable prices. Assuming thats a sound you like, that would be a better place to start that low end bookshelves purchased new, IMO.
Paradigm Monitor 9s -
http://minneapolis.craigslist.org/dak/ele/2005214386.html
d luck.