I know that many New Line titles done by Mi Casa are re-equalized/optimized for home theater to reduce the brightness/ X-curve factor, but is this a standard practice with most films released today on dvd?
I believe it is, especially since home speakers are by nature brighter sounding, as they don't typically go through the same abuse theatre speakers do. Also, the bit rate on home DD 5.1 tracks is higher, as all Dolby can fit between the sprocket holes (where the data is stored) is a BR of 320 kbps. The typical DD 5.1 track on a DVD is 448 kbps and in some rare instances 640 kbps.
But remember - even at 448kbps or 640kbps, the sound is compressed. It can't compare to the same source in uncompressed PCM or other lossless formats like DTS Master Audio or Doloby Digital TrueHD as found on high definition discs. I can't tell you the number of movies I have on Laserdisc in PCM that sound leagues better than their DVD counterparts (sometimes even the Dolby Digital tracks on the Laserdisc are much better than the DVD editions though the bitrates and compression are the same - perhaps different mixes were used or too much processing done for the DVD versions - HELLO, DOLLY! anyone?)