I don't know yet if Google's Gmail is no longer invite only. But if it is and any of you want one, send me a PM and I'll see what I can do about sending any of you an invite.
Out of all the free email services I would have to say gmail to be the best. I also love the fact that you get free pop3 access with it while mostly every one else charges you for it as an extra service. As for security I use Kmail and PGP.
Also you should allways have an email address separate from your ISP. If for any reason your ISP is cancelled for what ever reason you're screwed. I never use my ISP's email just for that reason.