I agree, Gmail's come a long way and so has Yahoo's mail......still I can't get by with all my mail in the cloud. Outlook wins just by keeping it local.
Gmail also suffers by not having an equal to Outlook's Categories. I tie my calendar, contacts, tasks, emails, onenote, etc. together with categories and the best equivalent Gmail can come up with is labels and multiple calendars....not even close.
Try this in gmail...When I open Outlook I can see 2 ISP email accounts, 2 business wesbsite email accounts, 2 gmail accounts and 1 hotmail account all at the same time.....no forwarding. My filters automatically pull certain emails from all accounts and store them in the specific folders I've setup. My Outlook Today home page lists all mail, IMs, tasks, and appointments for today or up to 7 days at a glance.
If I only had 1 email account then it would probably be gmail and I probably wouldn't need Outlook.
edit:forgot an important part....syncing with my phone.....if the damn phone didn't tell me when and where I'm supposed to be and what tasks I have to accomplish, I'd be fishing 24/7