I have mine in this order.

Prev, Next, Play, Stop, Pause

For me this configuration works out best as Firm keys 1,2, and 4,5 are easy for me to work by feel alone. Also, having similar functions grouped together reduces travel time when operating the remote, previous and next in particular. I end up using Pause the most actually. For whatever reason I seem to always be pausing whatever I'm listening to or watching. Having Pause programmed to Firm key 5 works out well for me in this case.