hacked and hawked

My eBay account was hacked a second time yesterday. Passwords have been changed and I've sent emails to my ISP and eBay. I'm scratching my head over this. Is it personal with this guy? Are there any spyware or other security breeches or anything that this person could use on my Mac running OS 10.4.3?

Somebody requested that I post pictures of Studebakers. Here's a picture of my Hawk when I brought it over to the body shop last fall.