I have a pair of Beolab 4 PC hooked up to my PC, the sound is very nice for PC speakers. However, they are not magnetically shielded. So my iphone buzzes every so often
The BL4000s are shielded and would be an excellent addition to your set up, and you can use the speakers in the future for another function.
The zeppelin sounds great, but you have to audition the various speakers. Bring you iphone with you to hook up, because you might have a different compression rate than at the store. Price wise, the B&W is the most affordable, but for value, personally, I should have invested in a used pair of 4000s.