I have used Digital Dolly for years and find it very good. I had Partition Magic and found no advantage over DD. I like it because of how simple it is to use. It has a Help button for every feature. It remind me of DOSSHELL (I loved DOS ~snif snif~
I would expand D:\ as far possible then transfer all of E:\ to D:\. Once the transfer is complete absorb E:\ into D:\. This will leave you with C:\ and D:\.
I would defrag both at this point and and then you can resize D:\ if you want, then allow C:\ to have more space. Remember to defrag after words.
Remember to backup EVERYTHING!!! Do that before attempting to modify any partition.