I seem to have a taste for expensive hobbies. Right before really getting into brewing I spent $1.5k or so on an almost complete re-do of my computer. The only thing I didn't do because it wasn't too old at the time was the video card. Been thinking about upgrading that, but been so busy with other stuff I don't get much time to play anymore anyway.
Also used to fly RC airplanes. Have a gas Big Stik trainer type plane, a couple electric flying wings, and a couple thermal gliders. Moved during college, didn't really have the time or space to fly them. Right around the time I stopped flying the batteries were starting to die from the abuse I dished out. Between where I left them and the couple years they haven't been touched, I basically would need a complete replacement of all batteries.
I actually popped into the hobby store the other day. When I stopped, Li-poly batts were just getting started. Looks like they're pretty much the thing now, which means in addition to new batteries I'd also have to get chargers, etc. I'd need something in the neighborhood of $300 to get everything up and running again, but at this point I'm lacking the time more than anything.
There are a lot of things that I don't even think of as a hobby like that. I have been doing my owner computers for quite some time too. I just upgraded my HTPC to 6GB of ram, through in another 1.5TB drive for storage and had to upgrade the OS to a 64bit one to take advantage of that ram, also put in a bluray drive.
This thing is a beast, I have the raptor 10K hard drive for my OS/application drive, but this is the machine that supplies entertainment to the whole house or a lot of it at any rate. I am hardly ever on it because I don't have an actual monitor hooked up to it, but it is split to the master bedroom, the pool room and to the receiver in the living room which then can be split between the Rear projection TV or the Front projector.
Life is sweet in the living room with the 150" screen 18" 550 watt sub by elemental designs, I got their tower setup for the front and their center channel too. It is great stuff, the sub literally shakes the house, the SWMBO always has to turn it down, but it gives good back massages while sitting on the couch. Anyways, I use to frequent avsforums for all of that stuff, but since I have got back into brewing I haven't been over there.
Photography is a huge one, I had my first digital SLR stolen a while back and the new model of what I wanted wasn't out so I decided to go backwards to film for a while when I bought a Canon 1v-HS, the best film camera that you can find in a lot of peoples opinion that are not nikon people. Since then, I have picked up a 40D and a few nice lenses 17-40 f/4L, 24-70 f/2.8L and 100-400 f/4.5-5.6 L and a whole bunch of accessories to go with them.
Since I bought my house, I have become a handy man. I have taken a 40 year old house that really didn't have any renovations what-so-ever and upgraded/updated almost everything.
Anyways, brewing is great! Gotta get back to work now.