Things to look for in scanning software:

1. Supports scanning directly to raw files as either TIFF or .DNG format.
2. Supports 48-bit color

VueScan Professional and Silverfast¹⁾ support these features.

ScanSpeeder²⁾ is tempting because it supports scanning multiple photos at once (as does VueScan with "Multicrop" turned on³⁾ and Silverfast Batch Scanning⁴⁾), but it does not support 24-bit color and therefore is not recommended for archival scans.