What do you recommend for a solid state for office

Can't imagine you'd be going very loud in an office so most anything with the right features for you should work quite well. What's best for another may not be what's best for you. I'd focus on well reviewed products with the features you need and things should work out well.

Are you using PC audio? Need USB in? What kind of speakers are you driving?

Bel Canto S300i speaks for itself for half of what you want to spend for used unit. It will work with bookshelves like magic
Outstanding performance at any volume level, precise and detailed and very analogue sounding similar to class A amps or tubes, compact size, never runs hot and also an eye candy.

rogue sphinx

Second for the Rogue!