Debian is the Linux that least makes me want to kill myself. Generally installs correctly right off the bat with a minimum amount of bullshit involved. However, like most of the friendlier distros, it inevitably installs hundreds of packages you probably don't need even if you tell it to go for a more minimal install, so expect to either spend some time uninstalling stuff post-installation or have a bunch of useless crap sitting around taking up space. Also, whatever you do,
don't
install it with a graphical desktop right off the bat, it'll up the useless-crap quotient by at least a factor of four. Add that afterwards. It's a pain in the ass, but less of a pain in the ass than uninstalling tons more stuff you don't need.
A nice desktop would be XFCE (highly configurable, easy to use, and not too heavyweight,) or LXDE (lighter than XFCE and also quite configurable, but last I checked you had to do a lot of manual config-file editing to tweak it from the default settings.) Steer clear of GNOME or KDE; at this point they're basically entire mini-operating systems that install themselves on top of Linux and bring their fourteen billion dependency buddies along for the ride (because when you're choosing a graphical desktop,
naturally
you want to also install their media-stream framework of choice, right?)
If you're up for it, though, I'd skip the prepackaged desktop environments altogether and experiment with finding a combo of window manager + file manager + etc. that works for you. My current go-to WM is WindowMaker, which is a NeXTSTEP clone that gives you a nice all-in-one solution for window manager + session manager + applications menu + dock (a lot of the other independent WMs only do one or two of those and expect you to use some other utility to handle the rest.) For file managers, PCManFM (LXDE's file manager) or Thunar (XFCE's) are full-featured enough to be useful without getting in your way with duzitall whizbangery the way the GNOME or KDE solutions do, though both of them are still fairly heavyweight (just not as ridiculous as Nautilus or Konqueror.) For a much lighter-weight solution, xfe basically works, although it's a bit on the ugly, clunky side.
Photoshop does not exist on Linux, no. GIMP is the oft-touted Free And Open-Source Alternative, except that its user interface sucks ass. Still, the functionality is there, though if I were you I'd see about using MAME and Photoshop instead.
Computers: Amiga 1200, DEC VAXStation 4000/60, DEC MicroPDP-11/73
Synthesizers: Roland JX-10/D-50/MT-32/SC-55k, Ensoniq SQ-80/Mirage, Yamaha DX7/V-50/FB-01/SY22, Korg DW-8000/MS-20 Mini/ARP Odyssey/M1/03-RW, E-mu Emax HD/Proteus/2, Rhodes Chroma Polaris