I have used really high-end helmet mouted display
setups. They were awesome,
but cost upwards of $20K. An Asus GeForce3 Deluxe is around $400-500. There
isn't much of a middle ground :)
I bought my Visiontek Geforce 3 ti200 yesterday at the Gateway assessory
store for a net price of under $100 ($185 plus a $26 mouse to get over
$199, then $50 instant discount using code BA686, plus $14 tax, free
shipping, and finally a $50 mail in rebate). Or just stop at a SoCal Fry's
for $99 this weekend on a generic version.