An early 70's Fender J, that a local luthier (Paul Saunders, who is now semi-retired) fitted with DiMarzio J-PUPs, VVT controls that were also pull switches for coil switching (the two Volume controls) and control bypass (Tone control).
Played like a dream (even to me as a player of only 6 months), especially after he had not only refretted and setup the thing, but also refinished the neck. Had that growly, mosnterous, funky J tone! Man...
Can't even remember what he was asking for it. But to this 17 year old (at the time), anything was too much!
Other than that, there really hasn't been another instrument that I was "Jones-ing" for, with exception of my now 99% done P-bass copy...
EDIT (3 minutes later)- actually, yes, a Spector NS-2 from the late 80's. Yeah, would love THAT tone (think Alice In Chains)!