manual focus - How will old M42 lenses work on a Nikon camera?

I wanted to get some cheap old lenses to use on my Nikon DX DSLR (D3100).

However, Nikon has one of the greatest flange distances of all manufacturers, which means that most lenses I can buy (M42 mount, etc) will not focus to infinity. I saw some adapters with correction lens to allow infinity focus, but also read they worsen picture quality.

Has anyone here used this kind of setup?
(M42 cheapo old lens + adapter to Nikon with/without infinity focus correction lens)

If so, what can I be expecting, quality-wise? I read M42 lenses are not that bad, and I only have DX lenses, so I would not be expecting heavenly performance.
Basically, I'd like a nice big tele lens (300mm+) and the ability to focus it to infinity.

Example pictures would be awesome, and particularly I'd like to hear some interesting opinions complemented by example photos of the setup I'm talking about — a picture is worth a thousand words.

Answer

Having recently gone through this exercise first-hand, I'll share my results.

I bought a Helios 44-2 58mm F/2.0 (M42 mount) on eBay for very cheap. To use the lens with my Nikon D7000 body, I bought a Fotodiox Lens Mount Adapter which includes a removable infinity focus correction lens.

Shooting with the infinity focus corrective lens, I was very disappointed with the quality. Unless used with a very small aperture, the shots were not usable at all. Even when stopped all the way down, it was still soft when pixel peeping. It also seemed prone to a highlighted area in the center of the image. Here are a few test shots I took in the park.

Sorry I don't have the exact settings used for each picture. It's a fully manual lens (including an aperture ring), so the aperture doesn't get recorded in the EXIF data of the photo.

Being disappointed with my initial results, I removed the infinity focus correction lens, and tried again. This time with spectacular results at Howard Peters Rawlings Conservatory. Except for the first one, all shots in this set are taken with the Helios 44-2 lens.

So what have I learned? The infinity focus corrective lens is a waste. The Fotodiox adapter still works great without it. The lens works great on a Nikon body as a macro lens. And since I can't focus on anything more than a few feet away, that's all it can be used for. Considering how little I paid for it, I think I'm ok with that :)