I would stay away from any automagicall optimizers, in my experience they never work well, I have yet to see one that does good job and doesn't messup textures too badly3ds max has ProOptimiser, which allows you to protect the UV mapping whilst reducing the vert/poly count. I have found it to be very effective
I do lods manually. If my edge loops are good enough, this process is not that bad
also as Ben and stereo says
the big initial reducement should be deleting all the small bits and pieces that you won't see form futher away, and for the really low lods it is easier to build them from scratch and just re-use the current texture
also one big AC thing .. when savign the lods .. DO USE THE SAVE CAR WITH NO TEXTURE, since texture will be already in memory from the LodA, this way the lods are way way smaller files
most people are probably already doing it but it doesn't hurt to mention it