Your post really got me thinking. What would I buy with that budget? I'd probably want to mix up a few games with deep rule sets (that lead to long games) with some simpler non-mode based classics.
I would get
Deep Mode Based Games
Ripley's Believe it or Not $3800
The Lord of the Rings $5900
Non-Mode Games
Elvira and the Party Monsters $1800
Black Knight 2000 $2500
Cyclone $1500
Something In between
Stern Star Trek Pro $4000
I agree with past posters that it's key to play as many machines (both real and virtual) as you can. Since you'll be owning these games you'll want to make sure that they have a lasting fun factor.