The great majority of tablets out on the market are meant as entertainment and media devices, they are not really meant for work. For example, you might be just fine using any tablet out there to occasionally check up on your email or look up directions online to someplace, but how much would you love to type up a detailed proposal on a tablet touch screen, or try to make changes and design work on the touch display? You can't really just install your Quickbooks software, or your Flexi or Adobe Photoshop either.
If you're looking for a basic contact tool, like web browsing or email access, even task lists, then any tablet out there will do the job. I'd recommend the Google Nexus, there are four sizes available to fit your preferences, and it's well regarded as the best Android tablet out there especially given the price.
However, if you're looking for an actual production tool, then you're probably going to be looking into a Windows 8 tablet. If you get a Windows 8 tablet, you CAN install your normal desktop software (such as Quickbooks and Adobe) and do everything on it that you could do on a desktop system.
There are a few options out there for a full Windows 8 tablet. Microsoft just released the new Surface Pro, which comes with a much more robust processor and the full Windows 8 Professional compared to the originally released Surface RT. I'd also suggest looking at the new HP ElitePad 900 which seems really nice and has some optional accessories which seem great for a very mobile workforce.