Recently, I came across a page that lists 40+ tips for GMail users. Three of them are my favorites-
1. GMail Drive- Adds a new virtual drive(’Gmail Drive’) to ‘My Computer‘ folder and uses GMail as its storage medium. Drag and drop files Gmail Drive and it will store them on your GMail account as if on additional hard drive. For people like me who forget to carry their flash drives, it’s a very good option.
Here’s the link for adding GMail Drive.
2. Customize Google- This is an add on for Mozilla Firefox. It removes ads from the Google search page, inserts favicons for the different websites, switches your GMail and Google Docs account from http to https, hides the spam counter, has a quick contacts box, invite box and forces fixed font in GMail. I would suggest that you really give this one a try. You won’t want to switch back 
3. What do you do in case your GMail account gets full? Check out this page. You can take advantage of some POP settings and forward all your emails to another account.
There are many other tricks that have been provided in that page. For example– You can simultaneously sign into two GMail accounts, force all “mailto:” links to open in your GMail inbox, Better GMail etc.
Posted by Swen on September 20, 2007 at 4:30 am
Nice list. And i c they have GMailFS so u can mount Gmail on Linux too. (Am sorry had to mention this
)
Posted by ruhi on September 20, 2007 at 10:57 am
@Swen:
Great! Good to know that you’ll find it useful too. Btw, I ordered the Linux CD. Let’s see how it goes
Thank you for providing me with the link!
Posted by Patrick on September 20, 2007 at 10:38 pm
gmailFS is nice; I actually use it myself. what linux cd did you order?
Posted by ruhi on September 21, 2007 at 1:06 am
@Patrick, isn’t the gmailFS pretty neat? I came to know about it only a week back; it’s so damn cool. I ordered ubuntu (Swen helped me out actually). Which one do you use?
Posted by Swen on September 21, 2007 at 1:10 am
@Ruhi
Just doing my bit..
Posted by ruhi on September 21, 2007 at 11:02 am
@Swen:
Thank you
I appreciate it. I had no clue where to even start. The sooner I get of Windows, the better it is.
Posted by Swen on September 25, 2007 at 1:20 am
@Ruhi
Well its going to be a fun ride. a bit difficult, but fun nonetheless.
Posted by nishu on September 27, 2007 at 7:57 am
nice tips .. but u will find more on gmail’s official blog ..