I know that you've pointed out that the Search page isn't available in the Preview yet, but when it is I would love it to search across all categories.
What I mean is that back in the Zune desktop application when I searched, I immediately was presented with matches from my music collection, video collection, music or video stores, available podcasts, local podcasts, Zune users, etc. and if I clicked on any category I could see all the results from that category.
Similarly, web search with Bing and Google has offered something similar in that we can pivot by vertical categories quickly.
When I search on Photosynth, I'd like to see results for:
Photosynths and Panoramas (Titles, Tags, Descriptions)
Comments on synths
Forum discussions (Titles, Users, Full Text)
and then be able to drill into any of those results categories for more.
I must be forgetting some obvious categories. Feel free to add them below.