For European high-end bikes, I think Veloflex Criterium 240 gm tires are the best choice. These are made by the same hands that used to make Vittoria tires. World Class Cycles (in NY) always recommends those tires.
For Asian bikes, and for euro-bikes that came originally with asian tubulars, I use regular Panaracer Practice 270 gm tires. I have been using them for more than a year now on my Carlton, and I like the looks and quality quite a lot. They are replacing 'Raleigh Nylon Extra JAPAN 270' tires (almost certainly by panaracer) that came on some of my raleighs :
http://www.ece.ubc.ca/
They cost about $25-$30/ea (non tourgard gumwall versions only, red and yellow tourgard versions are more ...) I would use Panaracer Rapide tires if I could find some with gumwall sides ..
- Don Gillies
San Diego, CA