up to you.
i still think the LCD-2 has more midbass, but overall bass, theres more with the denons. the denons will be better than hd 650 and have more bass.
i don't think you'll be missing out on a whole lot.
LCD-2 = the better headphone overall when considering detail, frequency response, distortion, square wave bass response, transparency, overall, its the technically better headphone. its more neutral with a dark tonality, very nice clean sounding headphone with amazing bass, some of the best bass around in terms of accuracy and texture/detail
Denon D7000 = the more musical sounding headphone, funner sounding bass, alot more sub-bass, less midbass, sweeter midrange, better treble, more comfortable. not as accurate in the bass, not neutral, not as transparent due to slightly grainy highs. i got rid of these since the LCD-2 where just more refined overall, but i do miss the denons fun sub-bass and musicality as well as their comfort
its preference really, i kept the LCD-2 over the D7000 since i enjoy its presentation and i found my modded denons to be a little too bright for me, both are great headphones.