I'm a big fan of Riise, and was livid with Houllier's treatment of him. Fine, he's not too hot defensively, but for his attacking instincts alone I'd have him pencilled in every week. The only left-back in the Premiership I'd think of playing ahead of him would be Wayne Bridge, and he's hardly the most consistent performer.
If you want LFC playing more attacking football, it'd be madness to consider not having Riise in the side.