Now if I didn't scare you away then I would highly recommend getting a Dell Tower server for your home webserver. A PowerEdge SC430 would more than do the job.
http://http://configure.us.dell.com/...c430sapp&s=bsd
My server configuration recommendations would be a Celeron 2.53, 512MB of ram and a 80GB hard drive. That would power your blog nicely. And its only $449 as of 2-23-06. Anything more than those specs would be over kill. You would run out of bandwidth before you ran out of server processing power.
If you don't already have a high speed connection I would look into SBC Yahoo DSL Pro package. Its 1.5 mbps to 3.0 mbps down and 384kb/s to 512kb/s up. That would power your blog nicely.
Depending on how graphic intense your blog is I would guess that it could support 10 to 30 users at once. Hope this helps. Let me know if you have any other questions.
