If you are using QTP, then you should seriously look at the http://oblivion.nexusmods.com/mods/26038 version. 'Reduced' has removed 400+ files that were the same size or Larger than the textures included in QTP3-Redimized.
The tool 'http://skyrim.nexusmods.com/mods/12801' performs "Textures Check, Fix, Compress, Improves Perfomance. Extra: Optimizer BSA." Many hi-res texture replacers are at 2048x2048 resolution, but will be just as beautiful at 1024x1024 and have less impact on your system. In that case, this tool gives you the ability to convert all the textures in a folder to the same resolution of either 512, 1024, or 2048. Very handy for combining some textures from different sources that come in different resolutions.
'http://skyrim.nexusmods.com/mods/19337' is a utility designed to aid users in merging files from different texture replacement mods with previews and automatic copying of normal-maps, glow-maps, etc.
'PyFFI' is used to optimize meshes. (If you don't know the difference between meshes and textures, check out the TESTG 'General Information', Glossary, and Utilities pages, referenced below.) See the thread 'http://www.gamesas.com/topic/1402681-pyffi-getting-a-bit-overwhelmed' for the basics. Also 'http://www.gamesas.com/topic/1326044-pyffi-vs-nifopt-vs-bsaopt' to see about the alternatives.
Check out the thread 'http://www.gamesas.com/topic/1386133-which-tool-to-optimize-textures' for peoples experiences with them.
I've bookmarked probably 50 threads on the subject of 'graphics mods', most of which are collections of recommendations. Some the best of the most recent are:
'http://www.gamesas.com/topic/1381981-new-rig-new-decisions-texture-packs'
'http://www.gamesas.com/topic/1422172-best-graphic-overhauls-for-2012'
'http://www.gamesas.com/topic/1390645-best-graphical-mods' (helpful to know what to avoid if you do NOT have a powerful rig.)
'http://www.gamesas.com/topic/1431982-graphics-overhaul-mod-recommendation'
'http://www.gamesas.com/topic/1357172-alternative-to-qarls-texture-pack' (because QTP is often just too much of a system drain)
'http://tesalliance.org/forums/index.php?/topic/4187-list-johns-list-of-graphic-mods-for-mid-range-rigs' (on the TES Alliance site)
'http://www.gamesas.com/topic/1412599-skyrimized-cliffs-mountains-peaks-etc'
and of course 'http://testg.wikidot.com/main' as a general resource. Once you start browsing that site you will see there are a number of sub-categories of graphic texture mods. If you can narrow down the focus of your inquiry, you will probably get more useful recommendations.
-Dubious-