Kind of depends on what you already *have*.
My first thought is a job [:D] but, for more fun, I'd say:
Good progressive reloader (my hand hasn't been this tired since I was 15).
M1 Garand, preferrably vintage.
M1 .30 Carbine.
Sharps repro in .45-70 or .45-100.
Helicopter lessons (damn things go for ~ $225/hr here).
Electronic powder dispenser with digital scale.
Lots of factory .45ACP and .223.
AR180B.
S&W M65.
Comp-Tac CTACs for my G21 and future G36.
Bull barrel and stock for my 10/22.
Mag extender for my 870.
Brownell mag tube dimple remover for my 870 so I can *use* the extension.
Markill titanium "Pocket Rocket" camp stove (uber gadget - it weighs 3 oz.)
VEPR-K in .223
Personal trainer and/or a year of training at any of the dojos I used to be able to afford.
A bottle of Balvenie Double Wood, Dalwhinnie or Macallan (there's a thread-merge for you).
Gift certificates to Sportsmans Warehouse and Cabelas for anything else I've forgotten.
And, um, maybe those aforementioned college hotties but only to cook the aforementioned steak. Naked. [naughty]
Edited to add: the ability to spell when posting. I used to be good at that....