The Web and a search engine is all that's needed with a Windows based tablet for apps. I find Apple's App store tedious to search from the Touch, and although I know there are a few apps in there I want (I've seen them on friend's iPods) I simply can't find them. Comparing PCs against Macs your argument for "unbeatable" fails. I've also seen far better (more efficient than the iPhone) UIs on non-apple devices. There is plenty of room for improvement there. It just takes some imagination.
Well now that you can use a desktop to search for apps, that's a slight relief - maybe Apple can provide a better search for app system on desktops, then give links to the apps/ buy the app and send a link to the iPhone/iPad/Touch to download them.
We await 3.2, let alone 4.0 - I think 4.0 should see some improvements.
There are always 3rd party app review options, recommendations etc.