I own the Uptown and the M50 (and have a broken set of the 840s that I got to demo for all of 10 minutes before the right earcup snapped off of the hinge), and the Uptown wins in most sonic regards, and the M50 wins in other regards.
The Philips has punchier bass, fuller mids, but has a bit of a peaky treble. The build quality is decent, but the cable remote, while a nice feature, isn't implemented very well. The cord is surprisingly durable, however, and is *just* the right length for portable use.
The M50 sounds decent. The bass is punchy, if a bit too loud, the mids are a bit recessed, the treble can get peaky, and the soundstage is rather small. Having said that, they're built like absolute tanks. I've heard some stories about people doing some awful stuff to their M50s (dropping them down escalators, for example) and them coming out OK.
Both are going to be huge steps up from typical, consumer-grade headphones. The M50s benefit from an amp, but still work fine without one. The Philips play very nicely with portable devices.
If you don't mind on-ear headphones, I'd take a peek at the JVC HA-S500s, but any of your other 3 choices will still be very nice.