How I Use Gmail
I am a compulsive e-mail archiver. My Outlook Express mailbox, which is compressed, weighs in at more than a gigabyte. However, a gigabyte would be more than enough for me (and almost everyone else), if it weren’t for large attachments. If the average mail size is 5kb, and you get 100 emails that you keep per day, it would still take more than 5 years to fill up a Gmail mailbox. It’s the attachments that really eat up your Gmail quota. However, I like the ability to check Gmail on the run.
What I do is set up a forwarder email address which forwards mail to two addresses: Gmail, and a regular POP3 mailbox. Outlook checks the latter, and I use Gmail when I’m out and about. Generally, I delete unimportant emails with attachments from Gmail to keep space usage down, but this still allows me to check my entire mail archives using Gmail while on the run. If I really need to retrieve a large attachment, I use Outlook Express to do it. People email me on the forwarder address, and I set the “From” email address field in Outlook and the “Reply-to” email address field in Gmail (since you can’t change the From address there) to the forwarder address.
Another idea: Gmail recently put the number of unread emails into the title bar of the web browser window. Since Gmail will check your mailbox for you periodically and update the title bar, a third party should write an application that monitors the Gmail title bar and if the unread emails number ticks up, play a sound or some other notification that you’ve got new mail. Google could itself build this feature into Gmail, but I guess there are issues with playing sounds through different web browsers.
1:35pm (GMT +10.00) tomorrow 
Freak … my Inbox (on my PC, not Gmail) contains all my email since 1999 – 2552 messages. And my sent folder all the mail I’ve sent since 2001 (1269 messages)… about the only thing I routinely delete is spam (well actually Mozilla’s filter does that for me). Together they’re 60mb. Yes, sixty MEGABYTES, or 6% of a Gmail quota.
And yes, people have been known to send me large attachments. They don’t do it every day, sure, but then if you get several large attachments every day it might be time to start yelling at the senders people ;p.
How you managed to have a mailbox of more than 1gb…??? Unless Outlook’s compression has a strongly opposite effect (which I think is beyond even a Microsoft product – there are limits), I really don’t see how it could happen …
I’ve hit the 2gig PST limit @ work 3 times in the last 3 years. At home I’m on a few 100 meg since about 99.
Work and sending Bmp attachments I’ll need later on are the killer.
–WaD