A tricorder. It would come in handy for diagnosing patients at work and it could tell me why my intestines really hate me right now.
Since this is basically a poll, I’ll move it to In My Humble Opinion for you.
Cajun Man
for the SDMB
7 of 9.
I’d go with the Heart of Gold. An improbability drive can do pretty much anything, right?
I was wonderin’ when I’d see this.
But I’d definitely want a flying, time-travelling battlemech with a fully fuctional 1920’s style death ray as it’s primary weapon. That, or a fully atomated Death Star.
Yes, but there may be side effects.
If the Borg collective counts, I want the Vorlon homeworld (and the ability to get there safely).
Damnit, now you’re ruining all my fun! 
Stranger
Gotta agree with you. A replicator would save me and my family from my boring cooking. And a large hash brownie with a glass of cold milk sounds WONDERFULL right now… 
GIR counts as a gadget, right?
(“I neeeeed tacos or I will explode! That happens sometimes…”)
I’d like one of James Bond’s cars, should make the Mass Pike alot more fun every day. Let’s see, should I go for the Jaguar with rocket launchers or go all-out for the Aston Martin with machine guns? Decisions, decisions…
Or maybe just an ornithopter to avoid the traffic altogether. Teleporters may be more practical but where’s the fun in that?
If we’re taking small ships I’ll take the Millennium Falcon.
You can pick up chicks better with the Falcon than a Runabout.
A holodeck would be the death of me so no thank you.
But a replicator, now that would be something worth having.
Chitty Chitty Bang Bang would be kind of cool.
R2D2.
Of course, he’s got to come with that translator periferic, you know, the golden thingamajigwhat’sitcalled.
And a remote to shut the golden thingamajig off when I don’t want to hear it whine.
Tang.
Obi, from the Well of Souls series by Jack Chalker
He’s a sentient, moon-sized spacecraft/computer/god, who is also a genuinely nice guy. We could travel around the universe doing good.