Porcupine Tree, Trains. She's sure to love it. Alice in Chains, the whole SAP Ep (or Just Brother), AIC--Nutshell. Mad Season, Long Gone Day. Chances Three, NM. 3 Libras APC, Nonexist instrumentals (like Ataraxia), Testament, Trail of Tears, QR, Silent Lucidity (or something slow off of Empire)....Rainbow--Stone Cold, and throw in a Solitude Aeturnus song.
Oh, and sneak in a Candlemass song. Pow! Right in the kisser!
Hey, Morbid Angel has a beautiful instrumental off of Formulas Fatal to the Flesh...just a thought. Can't remember the name off the top of my head.