I'm just getting back into biking after a long layoff, I have a cannondale killer v 900ht that i'm setting up to tool around on. I do 40 to 50 mile trips on street tires and love it. The only problem i have is sore butt, any recommendations for saddle?

Saddles are very personal. What works for me might not work for you.

I have a Bontrager Paradigm RXXL.

I can't really recommend a saddle. Check a with a knowledgeable local bike shop.

I would say, though, that if you can do 40-50 mile rides when you are just getting back to cycling, imagine what you will do when you've built up some endurance and gotten into better form!

If you are doing that distance with your current saddle and want to try others I'd suggest trying some saddles from a shop that will loan you a saddle for a few days with a full refund policy. Trek/Bontrager does so and many shops have liberal return policies. Pay attention to the curvature/shape of those that seem to work for you. Recommendations from other folks really is next to meaningless. A lot of us have a half dozen saddles because weight, ability, distance and other factors change over the years. Good luck.

Agree, find a shop that has a test program and an ass-o-meter to measure your sit bones. One thing to remember when you get the new saddle, contrast it against your old one and take note of your position on the old one and start to adjust your new one from the same point... if that makes sense. I had a new bike and could not get the saddle position right until I put my old seat on. Then when I went back to the new one I adjusted it to it matched my sit bone position - not the angle, not front to back...

There are a few of us in the Southeast Regional subforum (lotsa FL folks) and several 50+ folks who ride on Selle Anatomica saddles. Got one on both of my bikes.