I prefer tubed amps with headphones because the sound is softer and less fatiguing directly at ear level. I have and like the Cary cad-300 sei, which is probably out of your price range, but their are a number of tubed units that get good reviews. See the attached link below. I've had several Headroom amps and don't find any significant difference between their crossfeed signal processing ('music in the middle of the head') and normal tube amp sound.
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&992329746&read&keyw&zzantique=sound=labs
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&992329746&read&keyw&zzantique=sound=labs