Since I got back from holidays, I've been using Vista RTM in anger on a few machines. There are certainly a few annoyances (beyond the usual driver issues and app compat issues that seem to arise from using a new OS).

What happened to the View -> Folder Options -> Files Types tab that was in Windows XP that used to give us control over what applications, actions and icons file extensions were associated with? It seems to have completely disappeared. You either need to edit the registry, or use a 3rd party application to get this control back.

And what happened to the network icons we used to have in the notification area/system tray? We used to have one icon for each network connection (assuming you choose to enable that). This allowed us to see the status of each connection, and which connection traffic was travelling over. Now we have just the one icon, and the Network and Sharing Center doesn't tell us much about the status of each connection either.

When "repairing" a network connection under Windows XP, we used to get information on what the OS was doing, and at what step the repair failed (particularly useful if a DHCP server can't be contacted, or isn't responding). Now we just get bland information, and an option for us to "reset" the connection.

I have a few more annoyances, but they might be the result of me not knowing where the new options are. Feel free to add your own issues.