that doesn't sound terribly off but did you.........
allocate more memory for the wavesplug-insthis will drasticly improve the plugin count and cpu load while using waves plugs.
Also mess with the hardware buffer size in protools that could give you more performance.
and last but not least look at the cpu usage limit in your preference menu in protools see if its at say 40% or say 80%(max for one processor, only PT6 and up). If its at 40% it will only let you tap 40% of the processors power.

and by the way what effects are you using?

Thanks for the great input! I was using Channel, Reverberator, Compressor, Equalizer and Bass. Almost all of them! I did have my CPU limit set at 80%, but will play around with the buffer and see what happens.

i find that if using pc, the waveshell allows you to run a hole lot more plugs than the stock or other plugins around..
like nuendo 2.1 for example. i can use
24+ Rvox
48+ Ren eq's (mono or stereo)
2 Rverb
1-2 Trueverb
2-3 Rbass (when needed)
16+ Rcomps(usually mono,but stereo when i need it)
a supertap delay here or there, a few S1's and other plugins too.

to get these numbers i just opened up a recent session, and my cpu is sitting around 65-70%.
i'm using a Amd 2500+ clocked to xp3000 and nuendo 2.1.1

when i do work on ptLE system i always find the computers crap out rather quick. it can be a pc or mac. i usually see that macs handle more plugins than pc's when it comes to PtLE. i'll be getting a digi002R in a week or 2, i guess i'll see how many waves plugs i can run. i should be able to run more seeing that i'll be limited to 32tracks. the session i pulled up for those numbers has 56 tracks. everything was track 32/48khz(32bit float)