Neruda:
Did you know that the 350 for $300 was refurbished?
Funke:
Someone posted a link to UnitedOnlineShopping. That's actually where we bought ours (in fact, they had an open-box model that they had used to demo for one day at a show, so we got the L40 without speakers for $350. We already had a pair of AlphaAVs). You may want to ask them if they have any demos. That actually brings up another possibility -- if you decide against the Alphas (to go for the Axioms or something else), you can get the L40 by itself. However, the Alphas do match very well.
EDIT: I just noticed that the $600 at United Online includes the AlphaAVs instead of the AlphaMinis -- that means better bass, which is probably good for your music tastes, which include rap. However, it may not include speaker cables.
United Online also provides a replacement warranty -- if something goes wrong, instead of having to worry about findind an NAD service center, you just send it to them and they send you a new one.
Holy Zoo:
The L40 does have a pretty good headphone jack. It's definitely not as good as the X-CANv2, but I don't think you'll find a headphone jack built into any component/system that is. I'd say it's in the upper ranks of "built-in" jacks.
Funke:
To answer your last question: the separates Neruda mentioned would definitely sound better, given good cables. But if you want to buy them new, you're looking at $400 + $230 + $200 = $730, plus cables, so probably around $830 - $850.
Of course, as several people mentioned, you can go with used stuff. If you're careful, it's possible to get great stuff used.