Fonts: You can't change them in Mac OS X either. So unless you stick to Windows Classic theme or a Linux desktop I guess you're SOL. I do think that GUI customization has been F'ed up ever since XP introduced it's "visual styles" (and even before that , odd font sizes never worked that well), and would too like some more control over such things, but I think it does look pretty good as is (as does Mac OS X). Both Vista and Mac OS X Tiger have the underpinnings to make adjustable GUI fonts work well, but I don't think this is going to get fully realized in Vista, and Apple is going to beat them to it in Leopard.

You can, actually, but you need something like TinkerTool to do it. For a lot of people, though, that the same as "can't".
Search: I dunno. Search in general was broken in the last build I had (5308), but searching for apps on the start menu worked even then.

I can't remember which previous build I had installed, but it didnae work.
Dashboard: If you click on the background of the sidebar it will come to the top. Otherwise, I was going to suggest hitting Win+D to show the desktop, but that hides all the gadgets too. I think that's stupid so I filed a bug asking to leave them visible and/or add a "Show Gadgets" keyboard shortcut. Even though I'm not an official beta tester, they've fixed a couple of the bugs I've filed in the past so we'll see.

I'm one of the "install it for 14 days" beta testers too :)

The "show gadgets" shortcut is basically what Y! Widgets and Dashboard do. Although OS X does have the neato feature of being able to trigger this by using a hot screen corner. So I fling my mouse into the top left corner, and presto, the Dashboard appears. It has a dictionary, my Dynamic DNS updater status doodad, the weather and a calendar (I'm alarmingly bad at remembering what day of the week/date it is).
Toolbars/Menus:, If they hadn't laid them out pretty good I might be with you but I like what they've done so... Anyways, I see what dragable toolbars and "cool"bars and menus get you on our employees' displays. Toolbars end up in bizarre positions, where they have no idea how they got there and no idea (or willpower to find out) how to put them back. Maybe well designed fixed position toolbars are the way to go (I again note that Mac OS X does this as does GNOME now I think). I will admit to a certain desire to be able to add and remove toolbar buttons however.

The toolbars thing is going to generate huge training issues for no real benefit. There are hundreds of millions of users out there who, for better or worse, know how to work Explorer and IE with the interface that it's got as at Windows 2000/XP. It's going to take vast leaps of new productivity and ease of use to convince me that the wholesale change that's been implemented is a good idea. I don't believe that such vast leaps are forthcoming.

This bit also applies to the new interface in Office 2007 (I downloaded the beta of that today, too). Whilst a "power user" (ugh, I hate the term) such as myself can adapt (I think it's pretty funky, and it might even be proper good, although I haven't done any proper work with it yet - I'm going to have to reserve judgement on this), I can see the rank'n'file Office users floundering and floundering badly. If you're used to Edit->Fill->Series in Excel, and have been since Excel as of Office 4.3, this is a Big Lose.