Hi there gubi,
since you didn't provide any details of what kind of players you're talking about, one has to answer the question in general.
Because of the fact that it is discussed controversially if balanced conncections have that impact to the sound compared to unbalanced ones at all, I would definately go for the better DAC - where all the sound is being 'generated'. Besides that I have even read that some unbalanced outputs should have sounded better than the balanced in cases where the balanced connectors are physically derived from the unbalanced signal path thus sounding even worse. Of course, this statement is under reserve, I haven't checked this by myself.
Anyway, the best way would be to use an external DAC which is (almost) immune to incoming jitter. This way you can use the lousiest player as long as it is able to provide flawless data over its S/PDIF-output. In the case of Benchmark's DAC1 which already received rave reviews, you can get such an ultimate solution below 1kUS$ (about 1kEUR in Germany, brutto). And this device is pretty diplomatic here - it has balanced as well as unbalanced connectors.
More info under
http://www.benchmarkmedia.com/dac1
Guess what I'm going to buy in the near future ... ;-)
Kind regards,
little-endian