Conti Sonderklasse - these were a pair of 27 mm tires I won in a prime.  Amazingly fast and comfortable.  Lasted a full year in the back before being worn out.  When I went to replace them, I learned that they were track tires (>$100 each in 1999).  Still available but not in that size.

Conti Competitions - Continental's best raod tubular.  Very long lasting and available in a 25 mm version (used for Conti-sponsored teams on the cobbles).  Even for their best tires, they are lumpy (not evenely built and sewed together) compared to other manufacturers.  $60

Conti Sprinter - half the cost of a Competition, not available as a 25 mm, wears well.  Good for a spare tire.  $32

Vittoria Special Pave - measure a true 26 mm, the Mapei/Quick-Step tire for Paris-Roubaix over the last 15 years.  No longer listed on the Vittoria website - now list only a smaller Pave model.  My rear tire of choice for 10 years.  Front and rear for Belgium 2006.  $50-55 3 years ago.

Veloflex Criterium - gorgeous black/gumwall 23 mm (Record and Serviso Course are narrower).  Best built tire I have ever seen.  Super comfortable and my tire of choice for the front.  $60-65.

Veloflex Roubaix - 24 mm, all black (ugly) tire.  Great for front and back for most people.  My front tire when in Belgium and France in 2004.  Veloflex's quality in tubulars and clinchers is easily the best.  Italian workers hired from the old Vittoria factory when Vittoria moved to Thailand where the rubber plantations are.  $65-70.

Clement (now called Challenge) Paris-Roubaix - true 27 mm classic black/gumwall.  Well made but sidewalls are more delicate than on any other tire I have tried.  Much cheaper ($49 each) than the Special Paves but sidewalls blowout spectacularly before actually wearing through to the threads on the bottom of the tire when you've worn through all the rubber.  A great set of tires for our dirt road rides and Belgium.

Serviso Course - originally made by Clement and available from yellowjersey.org but now just named as above.  Extremely well-made and good looking $20 tire (in contrast to the poorly made $20 Vittoria Rally) that rides very stiff (even at 100 psi it feels like a clincher at 125 psi).  Relegated to spare tire status.

20 years worth of wheels in the basement means I'll keep riding tubulars until they peel the mastik from my cold, dead fingers however I do have two modern rear clinchers and a 20 year old front clincher.  I really like the Veloflex Pave (black/gumwall) on the front wheel - best riding clincher I have ever felt.  I also really like the Avocet FasGrip and Michelin ProRace2 25 mm clinchers (both measure 25-26 in reality), the Vittoria Open Pave (24 mm and very nice) and the Panaracer Rolly-Polly (true 27 mm with a tubular road feel and currently the rear wheel on my GTC dirt road bike).  All of these are about $40-45.

All things being equal (which they never are), clinchers have less rolling resistance, are slightly less expensive and easier for a novice to install; however tubulars have zero pinch flats and are more comfortable for the same size and tire pressure (but it's easy to change sizes and tire pressure).