Off Topic: Quite off topic, but if you use a tool like http://davmail.sourceforge.net/ , you can get Exchange email in any client. I recently switched from Evolution (because I don't like it) to Thunderbird 3, which runs pretty sweet on Ubuntu 9.10.
On Topic: I really only play one top end to-pay game any more. Everything else I get usually runs for free on Linux. If a native version of Civilization were released on Linux, I'd buy it. Hell, it would save be the $150 I need to spend to get windows just to play one game). And if a portal existed that provided other games with simple installation and payment, I'd buy those too. I've bought several games from http://www.gog.com/ that I run in Linux via WINE or dosbox. But if Steam was available with native builds, I'd probably buy those too.