Like most people I really dislike the chore of cleaning, but it probably shows how much of a geek I am when I admit that I really don't mind, heck even partly enjoy, cleaning my computer.
Most people don't bother cleaning their computers, but I like to run a well oiled machine (minus the oil of course). Typically it involves at least pulling out the dust filters and giving them a vacuum, but if I'm really in the mood i'll get an anti-static cloth and wipe down the fan blades (there are four fans in the Antec 902 I own), as well as wipe down all the internal surfaces to get rid of the finer dust that manages to get through the filters.
In my opinion, dust and the associated implications for fan efficiency and consequently heat build-up, is one of the bigger causes that affect hardware longevity.
It's been raining here a lot in the past few days, and it's hampered applying the final finishes to the exterior of the house. Things are coming along though, so hopefully it shouldn't be too much longer...