Anyone know of a comfortable seat that is compatible with Giant Bikes? I took my seatpost to walmart to try and fit the seatpost with the bell gel seatpost with shock absorbers, Had high hopes for this one but the two rails did not line up with the bracket on my bike. Trying to cut down on the impact from bumpy roads..and I already have biking underwear.
Almost all seats and seat posts use a standard width and size rail. Unless you have a very high end setup, it will be compatible. Since the one that you described didn't fit, I agree with the previous posters that the LBS has got it wrong somehow.
Note that padding is not the only way to reduce saddle pain: getting a saddle that fits is much more effective. If the saddle is too narrow for your sit-bones, or too wide, then no amount of padding will make you feel comfortable on it. That's got nothing to do with the size of your .... um ... ass ... rather, the saddle width has to match the bones of your pelvis. Some bike stores have a little gel ruler that you sit on and it measures the distance, thus allowing you to choose a saddle with the correct width.
I swear by the seats that have a hole in the center. Terry was the original but now other manufacturers make them as well. I have used them for years. Even with tons of gel the fragile parts are still going to be in direct contact with the seat and that hurts. If you do go that route, you'll have to adjust it a little here and there to make sure that it's doing what it's supposed to.