1. Google now offers Google Apps so that you could use you own domain with GMail. So I make it my spam filter since I think its capability is better than Exchange Server. The conversation view of GMail is simply awesome and in the future Office & Exchange 14 will included conversation view like GMail. What's more, Outlook Web Accessit be renamed Outlook Live, which will support other browser such as Safari, Firefox and Chorme with full features.
2. The Outlook 2007 problem has been fixed by Microsoft when you install Office 2007 SP2, which will be released in the near future. However, you could install the Cumulative Update according to the blog post.
I have tried it and it really works. The performance is significantly improved.
http://msexchangeteam.com/archive/20...24/450881.aspx