Cozy Grammar--We bought this several years ago after reading good reviews, but I never hear it mentioned anymore. My kids love this program because she makes grammar easy to understand. It's a short dvd lesson (no more than 10 min.) and then a worksheet. They find her amusing too.
Rainbow Science--we'd had great success with this program. The down side is that it's pricey.
Writing Strands--at least for the younger grades (haven't used past book 4.)