I'm trying to take a value in a given cell and round to the appropriate sig
figs as defined by a "user". I found a formula in here (Thanks to Jerry W.
Lewis, I believe) that will work for numbers below 1. However if the number
is one or greater, I would like it to report to the correct number of sig
figs and in scientific notation without insignificant trailing zero's.

Example:

453678 to 3 sig figs.
= 454000 or as I would like to see it 4.54 E5

I've tried converting it to a text and playing around with it that way,
based on some formulas I've found in here, but I'm not having much luck..

Any thoughts?

Thanks in advance!