Umm, isn't this the type of question that depends on what a person needs?
I use yahoo Mail Plus. I use a Firefox plug-in to check every 5 minutes for new messages and alert me if something comes in. I'm one click away from viewing my email with firefox, as my username/password are saved in the plugin. I go back and forth between school/home/work and so it's a necessity to be able to access mail from anywhere. IMAP is out of the question because my ISP/School doesn't offer it. Spam/Virus protection is brilliant, as it means I'll never unwillingly open up a virus email and I don't have a need for antivirus software (haven't use any in four years actually without problems), plus I don't have to bother with sorting through spam. Other benefits are that I never have to backup my email, I can have mail forwarded from other POP3 accounts to my main yahoo account, I can created "psuedo" addresses for use if I don't want to reveal my real address, filters, folders, address book, 2 GIGS of storage, POP3 access for backup if I really need it, forwarding, and the peace of mind that I don't have to worry about my ISP closing/merging, etc.
Yeah, webmail works for me. Although I can see why some people might not like it 🙂