I've got too many hobbies, the only thing keeping me from having more is the cost.
I guess my main hobby at the moment is using my Amiga for playing and making games, but my other hobbies include:
Retro gaming in general. I have a nice collection of consoles and games, most of the big ones up until the PS2. My boyfriend and I have turned our garage into an arcade/bar style games room, so all the consoles are set up with the TV in front of a couch, but we also have a poker table, pool table, dart board, a few mini pinball machines (not full size ones) and this IR bottle/can shooting game. There's also a mini jukebox CD player for music. I spend a lot of my time in there when I'm not making games on the Amiga.
Here are some photos of the games room -
http://www.spin.net.au/~amiga/GamesRoom001.jpg and
http://www.spin.net.au/~amiga/GamesRoom004.jpgApart from gaming and chatting on IRC, I also collect things. I have a collection of Cammy (a character from Street Fighter) stuff, including action figures, dolls, keyrings, t-shirts, cards, books and comics and anything else with Cammy in it that I can find. She's my all-time favourite game character.
I love to read comics and novels too. I have a big collection of comics, ranging from superhero comics to fantasy, science fiction, and funny comics. I review comics for a paperback reader website, as well as interview the writers and artists and write other articles. Some of my favourite comics are Red Sonja, Lady Death, Street Fighter, Supergirl and the Legion of Superheroes, Futurama, Teen Titans, New Avengers... the list could go on, I love them all!

Another thing I collect is action figures and LEGO. Most of the action gigures I get are based on comic or movie characters I like. I have nearly the full set of Stargate SG-1 figures, heaps of Pirates of the Caribbean figures (including the Black Pearl ship) a bunch of Marvel Legends, some Transformers, Star Wars and other various figures. My favourite LEGO line is Mars Mission, and I have most of the set.
Here's a photo of my LEGO -
http://flickr.com/photos/24340362@N08/2312415090/One of my favourite hobbies is something some people call "cosplay", or costume play. Basically I make costumes based on characters I love, and I wear them to comic conventions and for Halloween and stuff. The photo in my avatar is of my Street Fighter Alpha 3 Cammy costume. Other costumes I've made are two versions of Supergirl, Ravager from Teen Titans, Super SF2 Cammy, Red Riding Hood, Vala from Stargate SG-1, and I'm working on costumes for Red Sonja and Lady Death.
I don't know if you could call it a hobby, but I also love cats! I live with a cat named Black Magic, and he's the weirdest, crazy cat I have ever met, but he's also really sweet. He talks a lot, and he's really paranoid about standing on carpet, so he jumps on everything, and he can jump really high! We play lots of games together like tag and tug of war, he's a lot like a dog.
Here he is after a hard day's work helping us out in the games room construction -
http://www.spin.net.au/~amiga/BlackMagicAllTuckeredOut.jpgCars used to be a bit of a hobby for me when I was younger. I used to live out on a farm, and having no public transport out there, I pretty much needed a car to get anywhere. I had a 1988 2.0L Holden Camira which I modified with a nicer exhaust and intake, and I fully customised the vinyl/velour interior myself in this cool black and white theme (the car had bluish interior before I changed it). I was in a Camira car club and went on a few cruises with the club too. But I've grown up a bit since then, moved closer to town, and become more environmentally responsible by replacing the car with a bicycle, which has become a much more fun and less expensive hobby than the old car. It may not be as fast, but it keeps my legs looking good.
Other than all that, I also sometimes find time to do some cross-stitching, which is like making pixel images with string on fabric instead of on a computer display. I also love to write, and I'm working on some short stories, comics, and a TV series script. I also love natural, out-doors type stuff like bush walking, hiking, camping and even a bit of gardening (I grow my own vegetables, herbs and tomatoes).
Sorry for rambling!