I did just see an ad where it indicated that the code 55 would work better with the older rolling stock due to wheel size.
Actually, it's sort of the opposite. Code 80, being higher, generally works better with older wheels, some of which had overly deep flanges. The exception is PECO Code 55, which has an unusual construction and works well with all wheels.
Does DCC make any difference in which track you use?
Not really, although you will hear a lot of noise on this. The key issue is the way that the turnouts (track switches) must be wired with DCC. Some types require more gaps and feeders, but nothing too onerous.
Most people choose the track type based on the variety of turnouts and not solely based on the code of the track. For example, in N scale Atlas offers both Code 80 and Code 55, which is more finescale in appearance but has the issue with older wheels. The Code 80 is slightly easier to wire for DCC, but it's not a huge difference. The atlas Code 55 offers only a #5 as the smallest turnout, which may be too broad for some.
PECO offers Code 55 which requires some additional wiring with DCC and Code 80 "Insulfrog" which is a little easier to wire. Some folks find the way the PECO turnouts look somewhat unrealistic, but they are very space-saving.
And there are other brands as well. But there is no one-size-fits all.
Personally I've used PECO C55 and Atlas C55 on projects and both have been fine. I've also seen fine layouts built with Atlas C80 and other suppliers' products.
If you have a hobby shop nearby, looking at samples of the various track and turnouts to see what you like the best may be a help. Forum advice only goes so far.