You have a couple options available for setting up a decent sounding minimalist stereo system.

Option 1: an integrated amp with passive, i.e. not powered, speakers

Option 2: powered speakers

Common for both options: MacBook Pro as source and a combination headphone amp/DAC.

Option 1 gives you more flexibility and easier upgrades in the future.

Option 2 is super minimalist and combined with a good headphone amp/DAC can have very good sound.

for jazzfan's Option 2 above: AudioEngine 5 powered speakers. Speaking from experience, they're great straight out of a MacBook Pro and even better w/ a headphone amp/DAC like the HeadRoom.
(the B&W's you mention look cool and are probably good too, but I haven't heard them)

powered monitor speakers at the upper end of your budget should be on your list.

RG

Based on reviews and buzz, I would be checking out the Peachtree Audio Decco2 integrated amp ($800), which includes a USB input to access your Mac's iTunes library, and a headphone output.

Also based on Stereophile's April 2011 reviews of insanely affordable but quality speakers, I would listen at least to the Wharfedale Diamond 10.1 ($350) and the PSB Alpha B1 ($279).

If you don't have them, speaker stands would cost more - perhaps a couple of months down the road - but if you can carve out the space to get the speakers off of your desk or shelf, you would almost certainly enjoy the sound more.

I got a pair of Dynaudio MC 15s for the TV in my bedroom and they are nothing short of AMAZING for their size.  I also stream music to them via an Apple TV. Highly recommended ...