I race Dura Ace on the track and train on it all winter long on a fixie. Dura Ace does fine on wet roads with just a couple suggestions. First, you can get an Ultegra Octalink bottom bracket instead of the Dura Ace 7710 track BB. It's much more durable and carefree. It fits the same cranks and has the same dimensions, but is the best sealed of all the Octalink bottom brackets.

On the hubs, Dura Ace provides some seals that you can insert when you remove the axle and pop out the dust covers. They increase drag a little, but keep some of the muck out. However, people raced on Campy Nuovo Record road hubs for years without problems with the same bearing design and same weather protection. You do have to know how to strip and clean your hubs, and be prepared to do it every 2-3 months during the winter if you want to ensure your hubs remain as new. It's the care they get that will make them faultless for years of use.

That being said, sealed bearings have a place on the road, but sealed bearings tend to be a way to save costs on cheap hubs. Some sealed bearing hubs are lower quality in overall construction (quality of axle, quality of track nuts, precision of bearing seating, quality of spoke holes, etc.) while others manage to out-engineer a Dura Ace 7600 hub. In the former category are Surly's, Formulas, Miche, the inexpensive Suzue's, etc. -- they may work fine, and they can be better value for the dollar, but they aren't going to be comparable in quality to a Dura Ace gruppo. In the latter category are, first and foremost, Phil Wood hubs. Some would add Paul hubs and a few others, but Phil's are the gold standard.

Everyone gets emotional about hubs, but as for the rest of the components ... Dura Ace crankarms are about the stiffest you can find, and their chainrings are at least reasonably round, have a good tooth profile that's smooth and quiet, and are made of alloy that doesn't wear quickly. On headsets, you can get all kinds of rants about Chris King's, but they are like Phil Wood hubs -- pricey but superbly made. Dura Ace headsets are fine, but they are almost as expensive as Chris Kings these days. On seatposts, the Dura Ace had a bad reputation for a while for breaking the head loose from the shaft, but these days it's quite reliable. It does have a setback; if you need a setback it's a nice post. If you don't need a setback, the dual bolt adjustment of a Thomson is just easier and more reliable. On pedals, it depends on what kind of pedal you like. On the track, Dura Ace PD-7400 clip/strap/cleat traditional pedals are most common among sprinters and kilo riders. Gaining in popularity are PD-7700 clipless SPD-R pedals, often modified to use a toe strap in addition to the clipless setup. However, there are quite a lot of different pedals on the track, just like on the road, so go with what you like.

Hope this helps.