My Sega Dreamcast.
On the tenth anniversary of its North American debut, I found myself eagerly hooking it up to my HDTV, worrying that the LCD TV would be unkind to its SCARTy output. It's possible that the white wonder was suffering from a dose of stagefright as when I powered it up I was greeted by the familiar chimes but a black screen. Drat.
One cathode-ray-tubed TV later and everything was working fine!

Here are a few things that struck me:
Size: This is one small console, at least by today's standards - [190mm x 195mm x 78mm]
Noise: Despite being one of the smallest consoles to sit under my television, it's undoubtedly the loudest. The Xbox 360 gets a lot of flak for its industrial-strength fan, but between the GD drive and fan, the Dreamcast creaks, whirrs and clanks like a troupe of badly oiled breakdancing robots.
Graphics: Held up amazingly well - my graphical snobbery could have been lowered by owning a Wii, but the graphics were generally crisp and clear, and none of the games I played seemed as though they were impaired by lack of graphical horsepower.
Controller: Design quirks aside (the painful cramps the analogue triggers caused were seared into memory) but the two controllers I found held up incredibly well over time, delightfully free of the flaccid-analogue-stick problem that blights my elderly N64 controllers.
Games: The worst part of the whole endeavour - not because I had a single bad game for the Dreamcast, but because of the condition they were in. I found a spine with about 35 game-discs (8 of which belonged to Shenmue 1 & 2 alone!), reminding me that the jewel cases that came with PAL Dreamcast games were junk, and rarely lasted a week, let alone a decade. Last time I dug out my N64, I was excited by each unearthed cartridge, knowing it was almost guaranteed to work. I began to lament finding my classic Dreamcast games, as I knew the chances of them working were slim.
Neither of my Headhunter discs worked.
Sonic Adventure(!) didn't work.
Crazy Taxi(!!) Didn't work.
San Francisco Rush 2049(!!!) booted, but the game wouldn't load...
Jet Set Radio (!!!) didn't work... At all.
Ready 2 Rumble Boxing and its sequel both worked, but with heavy audio glitches.
Power Stone 1 & 2 both worked, making the entire exercise worthwhile.
The good news is that Sega totally dropped the ball on copy-protecting the Dreamcast, meaning that the only thing needed to pirate games is the internet and a CD-Burner (I'll get cracking on that over my days off.)
Sad facts of a misspent youth: About three years ago, my younger brother set the Dreamcast up in his room. The first thing I did when I booted up the console was review my memory cards to see how much respect he had for the literally hundreds of hours I had poured into the dozens of games.
I found a blank screen.
It was all gone - not that I'd actively miss it or anything - I've gotten by for eight years without needing that save data, but it would have been nice to be able to step back into those virtual shoes and have access to my unlocked cars in San Francisco Rush, or review my collection of toys in Shenmue, or compete against my teenaged former-self in Crazy Taxi for the high score.
I slightly begrudge the fact that I'm missing out on a snapshot of the past because of my brother's lack of gamer-etiquette - I mean, countless hours wandering around a virtual Yokosuka looking for sailors, and what do I have to show for it? [Answers in the comments, please]
