Ultra Definition model pack by R1chard for Point of View is awesome, but its crosshairs are not very convenient. They're very large, thick and bright (with the mod consisting mainly of darkish locations), and are likely to pop out of the scene when playing in stereoscopic 3D. For the good old one-pixel-thick circle for Xen hands and cross for (dual) hornet gun, extract this into the mod folder AFTER UD pack! Enjoy!
Even with this installed I still don't have crosshairs for some reason.
Edit: for some reason you have to go into the console and type "crosshair 1"