I usually set up a new account for each site or service that I subscribe to. I've currently got only 5 accounts but I've had over 100.
Using different account means that, if one starts getting spammed, it can be deleted (and replaced with a new account for the same purpose) without having to notify lots of different people about a change of email address.
It's never a good idea to use an ISP-based email account, because you'll have problems if you want to change your ISP.
If you're looking for somewhere to get extra email accounts which can be used with a mail client (such as Outlook Express or Windows Mail) as well as through web access, try Gawab. See paragraph 3, et seq, of my post here:
http://www.theanswerbank.co.uk/Technology/Inte rnet/Question407429.html
Chris