Want to upgrade the Nikon D60

Can anyone recommend a good upgrade body coming from the D60? I've had mine for 5 years - it's a great camera for its time but I feel like I'm being held back by the low ISO and the resolution. I'm running the Nikkor 70-300mm ED lens for most of my outside stuff, and I have the 55mm kit lens and an old macro lens as well.

I know Ken Rockwell isn't a fan of upgrading for more MP, but I think the higher ISO will really open up my portrait stuff. Will I be able to zoom in more on a 24mp photo than a 10mp photo? Seems like I would.

I'm running Photoshop CS3 so I have the processing power to take advantage of a good DSLR. I just don't know what my next move up should be, if any. D7100 I guess...any input is welcome.

I'd post some images but Photobucket is being lame at the moment - all my stuff is purely amateur. I just like to take good photos of my dogs, hobbies and trips.