grendel etc # USE="-opengl -real -flac -aac -musicbrainz -arts -kde" emerge -auDv amarok

These are the packages that would be merged, in order:

Calculating dependencies... done!
[blocks B     ] >=x11-base/xorg-server-1.0.99 (is blocking media-video/nvidia-glx-1.0.8762)
[ebuild  N    ] media-video/nvidia-glx-1.0.8762  USE="dlloader" 0 kB
[ebuild     U ] media-sound/amarok-1.4.0a [1.4_beta3-r2] USE="-aac* -arts* -debug -exscalibar -flac* -ifp -ipod -kde* -musicbrainz* -mysql -noamazon -opengl* -postgres -real* -visualization -xinerama -xmms" LINGUAS="-az% -bg% -br% -ca% -cs% -cy% -da% -de% -el% -en_GB% -es% -et% -fi% -fr% -ga% -gl% -he% -hi% -hu% -is% -it% -ja% -km% -ko% -lt% -nb% -nl% -nn% -pa% -pl% -pt% -pt_BR% -ro% -ru% -rw% -sl% -sr% -sr@Latn% -sv% -ta% -tg% -th% -tr% -uk% -uz% -zh_CN% -zh_TW%" 12,739 kB

Total size of downloads: 12,739 kB

!!! Error: The above package list contains packages which cannot be installed
!!!        at the same time on the same system.