LED's take next to nothing to power. Althought, my dad left his car sitting for about two weeks, in the winter, and the radar detector always being on (stupid fords) it killed his battery. But that was in EXTREMELY cold conditions. No, you dont have to worry about LED's taking power away from your computer.
You are only going up 60 watts, thats not that much. If i were doing an upgrade, I would want to go pretty high. Maybe the OCZ Powerstream 600W. Antec is very good, so you really cannot go wrong with the one that you are thinking of getting. But if it is just going from a crap PSU to a good one, than you dont really need a high powered one, just a good one. I upgraded to a 520W OCZ from my 520W peice of crap local computer shop budget bull**** overpriced POS PSU. That guy, I'm so pissed at him, what a scum bag. Sold me Jetway telling me it was one of the best. JETWAY!!! WHAT THE HELL IS THAT?! He was such a scumbag, I think he beats off to customers in his office. He has a two way mirror between him and the customers, and he is a scumbag, so... Lets not get off topic here.