In reply to drconline:
For that grade range, the best crags are probably Castle Inn Quarry and Penmaen Head which have extremely easy access, although they arent what I would think of as holiday crags, and are getting polished!
The crags on the Orme, particularly Lower and Upper Pen Trwyn are the classic sport climbing venues in this area, and are definitely worth travelling for, but the flipside is that below 6c, there isnt a huge amount to go at.
Llandulas cave and Waterfall crag at Dyserth have a few gems in the lower grades too, but hardly classic (The setting of Waterfall crag is far better than the actual climbing looks!).
Another option, is the Clywd crags north of Llangollen. Fantastic setting, and if you select the right crags, there are plenty of low-mid grade routes.