I actually was about to change my email address
for the same exact reason. I have been on ebay 9
years and have different paypal and ebay email addresses
there has never been a problem.
I used one email address for the first 2-3 years on
ebay and then switched but have used that one for the
last 6 years, but the spam has gotten ridiculous.
Also, a trick to use, in your auctions, put spaces in your
email address in your auction - this allows people to
see it but not have those robots harvest the email
address from the auctions.