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So far as I know, and correct me if I'm wrong, the stock HD650, HD600 and HD580 cables are 100% identical (except the HD650 cable is terminated with a 6.3mm plug instead of 3.5mm).
It was already stated, but no, the HD600 and HD580 come with the worst imaginable cable this side of AKG. Some HD650's were sold with that dainty little thing too. The normal HD650 cable (and the one sold as replacement for HD600/580) is much thicker. It's one of the nicer stock cables around in terms of build quality, but it's still the tangled mess that most major mfr stock cables are. HiFiMan can include a nice bit of in-wall, 4-conductor, pro-audio, name-brand Japanese mic cable in the box of a $400 headphone, and Sennheiser still includes that generic thing in the box with $500 headphones. It's kind of depressing.
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Better save money and get yourself a pair of D5000 or D7000 if you want keep enjoying HD650s comfort but if you don't mind much more heavier you can try HE-400 if it's a good pairing with your gear
Sage advice. I love the HD650 dearly, and I'm thrilled to finally have it back up and running, I really missed it while it was gone. But the HD650s are not, and never will be, bass intensive or treble sparkly cans. It's not what they're supposed to be, they're mid-centric relaxing, easy-going cans that still retain a lot of detail. It may be time to spend that cable money on a second pair of cans that compliment the 650's for the times when you want lots of bass.
The Denons are truly excellent at that, as are HE-400 if you'd rather have something that's a little more in the "balanced, warm, dark" vibe, but that extends more evenly in both directions. Denons are great for the "wow" factor of ultra sparkly highs and ultra low lows.
In my own personal experience I recently revisited the cable experience since I was testing my new HD650 drivers. I rigged up my old broken Cardas which managed to not throw a fit (if I wiggle it enough it still works, the other day I didn't een have to wiggle it.) I somehow missed the improvement last time around, but I'm now a cable believer. There's a definite difference. It's subtle, but it's there. But it isn't magically adding frequencies, but it changes the attack of frequencies. Think of cables as mild tuning, not equalization/tone-control. It's the last bit of adjustment after you've already got the rest of your system just how you want it. At a cost of about $20 per .05% of difference.
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I build the dang things and I will tell you no cable will just magically add a whole bunch of one thing. The differences are subtle if that.
If you don't like the bass levels on the HD650, you have a pretty decent budget to play musical chairs with other headphones. DT990 comes into mind for sure, then Ultrasone-something-something.
Chris no have a lot of experience with Ultrasone =(
*manly tears*
If only certain other cable vendors were as direct about what cables do and don't do
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I have a DIY pure silver (Neotech) cable for HD650. The sound is cleaner with less bass. If you want to experiment
you could try Mundorf Silver-Gold wire, it's said to have good bass.
Sounds about par with all I've heard about silver, and why I still hesitate to actually jump into silver. I get what silver does, and I'm not entirely convinced I'd entirely want it to do that
and I never really believed they would do much except empty the wallet. But maybe I misunderstood? My replacement cables for my HD580 has the quarter inch jack and I didn't order a quarter inch to 3.5mm adaptor, but I have one now. My cable is definitely thicker with bigger terminal housings, much better than the 580 cable. 
