What's the best finish for a wood cleaning bench to make it resistant to solvents?

On my benchtops, I use a clear polyurethane varnish intended for wooden floors and stairs. It is extremely durable mechanically. I do not know how well it will withstand prolonged exposure to oils and solvents; I usually mop up any spilled fluids when I am done using them and I never had a problem with them damaging the varnish.

I'll second that. My bench was built more than 40 years ago, was taken apart and moved once and is still intact, having resisted spillings of all possible fluids, oils, solvents.

I put down a sheet of MDF and then paint it with "floor and porch" paint. If it ever gets ruined I can take the MDF off and replace it cheaply. My benches here at work are subject to cleaners, solvents and acids daily and I have yet to replace a top.

Any of the epoxy based finishes should be pretty impervious to solvents.

Stainless steel or formica makes a nice solvent resistant finish. (Sorry.)