I’ve used a Nikon Coolscan IV to scan in a load of my fathers slides from the 60’s (See a few of them here) and – if you’ve got loads to do – it’s worth looking for scanners which have the ability to clean up your slides (Digital ICE on the Nikons) and restore faded colours. Either of these can be done in a editing program but it’s an awful lot easier to let the scanner software do the donkey work.