The link for this post isn't completely relevant too the post, but it's the 3rd blog this morning that mentions abandoning thick email clients for Gmail. I figured I might as well mention what I do.
I read my personal email on a bunch of machines, some running XP, some OS X. Like the bloggers I read this morning I switched some months ago to using Gmail as my primary mail client.
The usual practice is to use Gmail's POP support to pull older email to a thick client periodically. That way one retains ownership of data, but I believe this also deletes the messages from Gmail. I like having my searchable archive there, where the NSA can read it most readily.
I fork my email streams instead. All my mail eventually redirects to a domain I control, it sends one stream to Gmail and one to my ISPs POP server. This does mean I need to see spam twice, but that's how I periodically discover that Gmail is sending valid email to their spam folder. (In contrast my ISP's spam filters are now excellent, I really don't get all that much spam through that route.)
Bottom line -- Gmail is really good. Other than search, it's Google's hit product.