What is the best nas for small business mac and pc platforms

I've used a couple.  The NAS devices from both Buffalo and Synology seem more than adequate for the tasks. You'll need to examine the different models for drives numbers, sizes, and connectivity.

This depends on your needs and budget. This sounds like a small enough network that you are probably looking more for somthing user friendly and low budget. In that case newegg has lots of options here is a link:

http://www.newegg.com/Product/ProductList.aspx?N=100008028%20600016042&IsNodeId=1&Submit=ENE

Newegg also has pretty good descriptions and a lot of their products have videos if you are unfamiliar with how NAS boxes work. If you have multiple departments that will have different access you could possibly get sperate boxes for each and then give special network permissions out that would give you the chance to add more security and increase throughput as the traffic would be split amongs the NAS devices. Just remember if you need 1TB now you will probably need 2TB later so try to get 5x to 10x expected needs or a box that is expandable (multiple drive slots but you plan to start with just using 1). Hope this helps and goodluck it's always fun to buy new equipment!

we need 6-10 tb to cover out storage at this point.  Raid 5 if possible.

Thanks

Any reasonable sized NAS box should do the trick as far as space and RAID levels. Either of the above suggestions should work. Are you just using this for storage or are you running programs as well and what kinds of programs?