there's a recent thread discussing your situation (link below). I recently set up a system in a room that size (though I don't have the added attraction of the amount of glass you mention) and am surprisingly pleased with the results. If I were you, I'd go for it. Furnishings and acoustic treatments can mitigate the glass issue. The room size isn't an issue at all, so long as you choose the right gear (at your budget point you should have an easy time) and have some flexibility in how you arrange it.
http://forum.audiogon.com/cgi-bin/fr.pl?cspkr&1220749541&openfrom&1&4#1
http://forum.audiogon.com/cgi-bin/fr.pl?cspkr&1220749541&openfrom&1&4#1