Although a new source upgrade is never a bad choice for improvement...I would have to say in terms of transparency, coherency, and overall musical involvement...I would opt for new speakers...Epos m12s or even the older models before this one (El2 ?) would be a nice addition...they are often found used for 5-600 USD...as would SPendor 3/5s...if your NAD CD is close to 5yrs old...even a new cd/dvd with a 24/96 DAC will surpass it...