Finishing off my basement in knotty pine. Any recommendations for a sealer? I want to leave it natural looking. Thanks!!

I used a water-based silk polyurethane.

Use an oil-based polyeurathane... Satin finish. Clean up takes longer but I like the results better.

Put the poly on before you put the boards on the wall or ceiling. Its easy to get a uniform finsih if the boards are laying horizontally on saw horses or a table.

I found if you apply a sanding sealer first then your choice of finishes the grain stands out and the yellowing with most finishes in time slows.

I threw on a coat of poly on the backside as well before I put my pine on the basement walls. I shouldn't have to worry about moisture, but I did it just in case.

I sanded between coats on the front side too to keep it smooth.

I did the same as wanderer but I used steelwool instead of sand paper between coats.

SB, what's a "sanding sealer"?

I used 3 coats of water based poly on a wood wall in my family room. Hung up wildlife pictures 2 days later. That was in 2002, and now I took the deer pictures to my shed (man cave) and there has been significant yellowing. Anybody had better results with something else?

What ever you use just look to see if its non yellowing.
Since your doing this inside I'd choose a water based finish.

Sascho makes a great, easy to use stain and sealer. Their product name for the stain is "Capture". For interior applications you would use their "Symphony" clear sealer over the stain coat. Capture is offered in plenty of colors from light to dark. Their "Natural" is a very popular color. If you want to keep the pine clear, Symphony is a great product on its own as well. Sashco products aren't available in many places in Minnesota but Schroeder Log Home Supply in Grand Rapids offers it online as well a phone orders.