There is a lot of snobbery in sports when it comes to attire. Tennis and Golf are the most obvious examples of this (polo shirts, pleated skirts, and ugly plaid pants), but anyone who’s ridden a road bike on the trail with sweat pants and a cotton t-shirt knows "the look". "The look is usually given by Lance Armstrong look-alikes. That is to say they would look just like Lance in their US Postal kit and matching limited edition Trek if they were younger, skinnier, and much much faster. Ever show up to a Saturday morning run in basketball shorts? That’s "The Look".
Unfortunately, it’s hard for me to give "the look" when I’m wearing a swim cap and goggles, but every time I see a guy swimming in a racing jammer, trunks, or – and this last one is the worst of all – a one-piece tri-suit I want to push their head under water. Does that make me a snob? I think it makes me a purist. You’re not doing your stroke any favors if you wear trunks (which would more appropriately be called hip anchors) The racing jammer is a high cost way to hide your tan line from a bunch of people who really don’t care that you wore short-shorts into the tanning bed, and the unitard is most often worn by men who are embarrassed to be shirtless in public. (Note to the lap swimming men: please be advised, the uni – no matter what the fabric design, or how tight it fits – will not make you look thinner. Furthermore, just because you hang out with anorexic triathletes all day, does not mean that you are embarrassingly fat. Nobody at the pool cares. Save your modesty for the track where the extra pounds actually make a difference.)
Goggles are a personal preference. I don’t recommend swedish style goggles to anyone that didn’t grow up swimming in them (those of us that did may never give them up), but I also don’t recommend a giant snorkeling face mask with built in nose plug. You want to get a sleek pair of goggles that fit your nose (I recommend adjustable nose pieces, but if a fixed one works, go for it). You want minimal padding (rubber gaskets work better than foam). My favorite goggles are TYR, but I know plenty of other people that hate TYR goggles (like Brian Davis, who laments that Northwestern would only provide TYR equipment). Speedo makes good goggles too, though I’ve never bought them for myself.
Swim caps are all the same. Silicon or Latex? It doesn’t matter, whatever you’re comfortable with. Just wear the cap from your last race. If you run out of swim caps you aren’t doing enough races.
Now, back to the suit. (This is mainly for men, women can pretty much wear any competition style suit. Two piece suits may look out of place in-doors, but they are never unappreciated. I asked Herriott Sports Performance Triathlon Coach Teresa Nelson and she recommended the standard polyester speedo, it all depends on what causes the least shoulder/neck chafing)
Fabric: polyester suits (like the speedo) last forever. By far the best suits for training in terms of comfort, modesty, longevity (of the fabric) and performance (of you) are the Nylon drag suits (like the TYR polymesh trainers). Without doing anything special, one of these suits would last me a full year of college level swimming (the stitches start coming out after 52 weeks of 10-15k a day). I’ve had my current suit for three years and it still looks new. If you like a more traditional brief, get a the waterpolo cut so it doesn’t look quite so skimpy. Also, buy it big enough size that it’s not a struggle to get into. a little loose is fine.
Swimming is about gaining a feel for the water. You want to be aware of how the water interacts with your body. If you are wearing anything too loose it will pull your hips down, and covering your legs with a jammer will take away the feeling on your upper legs, leading to improper kick.
Ok, so I’m a bit of a snob, but the proper swimming attire will actually help you achieve a better feel for the water, create less restriction, and lead to far less chafing (whereas proper cycling equipment provides extra pockets). I hope this advice is helpful.