My biggest pet peeve: Why isn't barcode scanner functionality built into the Market application? Android app creators have embraced QR codes, but as a consumer I hate having to launch some sort of third-party barcode app on my device, take a picture of the QR code, and then navigate to the new application I desire. I want to scan and acquire from a single app.
I've got a few other gripes -- a robust website, local currency conversion -- but I'd like to hear from other Android users. What features and functionality would you like to see added to the Android Market? Please weigh in through the comments or cast a vote in the associated poll.