You might want to add Optimized Distant Land MAX to your list, and make sure to pyffi all your meshes!
AWLS (lit windows at night/during rain) has no performance impact and everyone should have it.
Likewise for Bigger impact than you'd think.
When I had a 256 MB card, I struggled with all of QTP3R installed. Which doesn't mean don't try it, but if you end up prefering it above all, you might just pick out the pieces of it that really matter to you and nuke the rest to get back some performance.
I have AWLS and optimized Distant Land Max too now that you mention it. I just installed AWLS yesterday, coincidentally. I will try out the Noise Replacer thing that you mentioned too, thank you!
I have been trying to read up on pyffi-ing things too, but I have to admit I keep getting myself confused. It reminded me why I have degrees in English and music and not in anything pertaining to computers. I tried to look up the PYFFI utility thing, and like a bunch of different things popped up that claim to do something along those lines. If you happen to know a page where the pyffi process is explained in a clear succinct manner, please post the link.
I keep discovering more and more that I need to learn to successfully mod my ES games. It's fun though.