i would thing the best apps are the ones that you use the most. I suggest seeing if you can get the app "appbrain" it rates apps on a number of criteria such as: popularity per country, demographics, latest apps
Another great site is Androidzoom.com which is basically a way to search the android market without using your tablet.
As for best Apps? so many to choose from. Probably most people will want to install Facebook, Google Maps and a Twitter client if not already installed. Recommend 3D Gallery for viewing photos and other media content, it's a nice interface so long as the hardware is up to it. A good file manager such as Astro will come in handy (often tablets come with ES File Explorer which does the job).
One of the favourite e-book readers is Aldiko, definitely look that up. And you can get separate messenger clients for MSN, Skype etc. Or use Fring and access them all in one go.
A lot of people will benefit from installing Office software. I like Docs2Go. With that you can open, edit and save word/excel/powerpoint files. Usefull for some, maybe not for everyone. But at least if you get an email attachment you can then see it.
Final thought is a task killer, presuming you don't trust Android to kill tasks for you. There are lots available the favourites being Advanced Task Killer and another called Advanced Task Manager. Don't just install them, consider setting their options to auto-kill task. If you use the tablet a lot these come in handy.
I`ve also bought 1 month ago an Apad 10.2" tablet pc from ebay ,hopefully like yours. But for last 15 days its not working ,its stucked up at the display where they show "wowpad" at lower right corner.That is before the homescreen comes.It can be restrated but stucks up again at the same point.
Did u ever have this problem ? or Please help if u can manage with the problem.
Thanks in anticipation.