gmail

I have used gmail for sometime already and it continues to impress me. It is incredible how they were able to come with so many incredible ideas as to fix e-mail completely. Even if they didn't offer 1 gig storage space gmail would still be my favorite mail service.
The conversation system is wonderful and so obvious that it makes me wonder why it took so much time for some company to invent it. The contacts system is a feature that I rarely used with my other e-mails, but gmail made it perfect.
Now if they would only remove the "invite a friend:" window from my inbox.