If you do IB subwoofers make plans for a future upgrade path. People usuallydo four 15's or four 18's IB to start just to get SPL high.
This gal is going to install 12 18" woofer IB. Three modules of four 18" woofers.
She installed her first module driven by a QSC PLX amp as was very impressed
compare so her previous store bought subs.
If you are limited to only one woofer then build a sonosub, EBS design tuned
to 17hz give or take. Choose a good woofer for an EBS design.
http://www.avsforum.com/avs-vb/showthread.php?t=867123
re: projectors
This forum is pretty decent, use it to do some research.
http://www.avsforum.com/avs-vb/forumdisplay.php?f=68
screens
http://www.avsforum.com/avs-vb/forumdisplay.php?f=23