Digital BW, The Print

I am scanning 35mm b&w negatives using a Microtek ScanMaker 35t into 
Adobe Photoshop v6.0.

Is there an optimal resolution for scanning? If so what is it?
If not, is there a general rule-of-thumb?

My b&w images were shot with Kodak Plus-x and Tri-X.

Can anyone suggest pitfalls to avoid?

Any other comments would also be very welcome.

Thank you.

David Douglas
douglas@...