Hello Bifford,
I have been using my Zipp 303 wheels for racing since the spring of 2003. IOW, I am heading into my fourth season with them. I weigh about 150 lbs and I have only had to touch them up (truing) twice. I have used them mostly in criteriums, but have also done road races and TTs with them. I think that they are the best race wheels that I have ever owned. (Note that I wrote race.)
That being said, I agree with the others in asking you want to use lightweight wheels like 303s for everyday use. I am a big fan of tubulars but these days I would never use them for training -- way too expensive, even if you fix them yourself. I understand the practical downside of tubulars as I rode them exclusively from the mid 1970s through the mid 1980s.
For everyday riding you also don't want anything too light (tubulars or clinchers) because you will suffer from reliability issues -- spoke breakage and the like. Personally (though YMMV) I use standard 32 spoke clincher wheels for training. Once in a while I will break out my Mavic Ksyriums (clinchers) for a fast or very hilly training ride.
Lastly, on clincher vs tubular safety, unless you spend a lot of time cleaning the old glue off of your rims, you will definitely run the risk of rolling a tire. I have done that twice (once training and once racing) and believe me it isn't fun. The one safety advantage of tubulars that I have experienced is that it is almost impossible to pinch flat them. I raced one time on my clinchers (a long story) and I hit a metal bar at 40+ MPH on a long descent and pinch flatted both tires. It was very hairy getting the bike stopped without crashing.
Kind of long but it sounds like you don't have much real-world experience with tubular (forgive me if I am wrong) so I thought that I would pass on my experience.
Hope this helps.