What assembler(s) do you folks use with FreeBSD?

[ograbme]

Howdy folks,

I've been playing with the gcc compiler along with Perl 5.8.8 (both
supplied with FreeBSD) and have enjoyed it.  I got to thinking about
what assemblers (hopefully of the 'free' variety) you folks have used
or may be using on FreeBSD. In my case, the standalone platforms
contain Intel x586, x686 and AMD K6-2 500 MHz cpu's.

Any recommendations re: assemblers that you've used and experienced
good results ... meaning you enjoyed using when needed.  LOL!

Thanks in advance.