For highs, I would suggest Focal. They're made in the same factory as MB Quart, and their entry-level line (Access) sounds wonderful, and they're affordable. A pair of 6x9's cost about $160-$200.
You could even upgrade to the Polyglass line, which is in the $400 range for 6x9's, I think. If you have no budget, go with the Utopia line - it's incredible, but really expensive. They also make incredible subs in the Utopia line, but they're over $2000 each. They're probably meant for extreme SQ purists, though.