<p>For mostly B & W printing, condenser head enlargers may be a better solution than colour oriented diffuser heads. The reason is contrast.<br>
I've owned both Durst and Omega enlargers with dual heads. For B & W portraiture oriented prints I'd generally use the diffuser head to get a 'softer' image. As far as lenses get an 80mm for MF film, 50mm for 35mm film. Get a high end enlarger lens (El-Nikkor, Schneider Componon-S, etc). If you're using a 'blad 500 series, spring for the very very best enlarging lens money can buy. If you require big printing making, make sure you have an extended length column.</p>