Well now you can with a little website called TopAppCharts.com. This is where I found the info for my last post: "Top 5 Home Search Apps for your iPhone or iPad.". But the site offers info on more than just home search apps, allowing you to type in a keyword and search for whatever app you desire. If you're feeling lazy, or just don't know what to search for, click on either the "categories", "games", or "more" tab and choose a topic from the given list.
You can search both free and paid for apps, and also for apps made specifically for the iPad. My favorite search is for the Current #1 Apps, which shows the best apps across all categories.
Go ahead, try it out and find those apps "you HAVE to have" before your freinds beat you to it.