I never had problems with these tips on large (>750) filesystems. Disabling lengthy boot-time works fine as well.

I get filesystem errors even with this tips. Do not disable lengthy boot time checks.

If you have some big partitions, do not enable full journaling on them. I experienced reproducible freezes (about 30 seconds) when enabling this on my 250GB home partition.

Did you try tweaking bdflush as described by Daniel Robbins?