I'd be very careful about using corporate e-mail for anything other than work. It's redicuiously easy for sysadmins to read everything in and out of their server and it's even more redicuiously easy to keep a backup of every e-mail going in\out considering the price of mass storage drives. E-mails are also stored in plain text, there's no need for encryption on the server's filesystem, and if there is for secure network, the admin has they encryption key! DUH!
Be cautious about IM clients, use a proxy and encryption if you work in a place where there may be a sysadmin who uses some actual routing equipment instead of a linksuck "boradband" router. They can pipe messages to a logserver and you wont even know about it, even doing packet tracing. Best would be to set up a SSH\socks5 proxy server at home and pipe all your non-work traffic through that. (even HTTP traffic)
I try to use an alternate browser for my screwoff time and one specific one for work. Easier to clear the cache for my screwoff browser and easier to route the traffic to my proxy.