Gmail may not be the best thing since sliced bread, but it does have its advantages:

1. As far as I know, ISPs (at least in India) do not give email storage space of the order of gigabytes.

2. A person who accesses emails from multiple computers (e.g. home and work) or even multiple email clients (as I used to -- Thunderbird in Windows and Mozilla Communicator in Linux) will not have consistent access to his emails (leaving the emails on the server is not much of an option when the disk quota is something like 10 MB).

3. IMHO, Gmail's interface is the best of the currently available web-based email services (Disclaimer: I have not had a look at Oddpost yet)

It almost feels as if The Other Road Ahead had Gmail in mind when speculating on the direction of desktop software. It's not fully there yet, but is definitely on the right track.