regardless of what you think you'll need, you can feasibly cut in in half and be able to survive.
Bring enough socks and underwear for a least 2 weeks - you don't know when the first time you'll be able to score a washer OR have time to do laundry.
Yes on any electronics. Don't overload on actual DVD's and CD's. Rip and have an external hard drive. If you can record any popular series current episodes - you'll be a very popular person! Right now my line is seriously into House and Prison Break. You GOTTA have a laptop to mentally survive. It will become your sanity break - whether to watch or listen, compose emails, track finances, etc. Crew areas and ports have hotspots - take advantage of them!
Bring a power strip. I've been on a heap of ships and you only have 2 110v plugs. Maybe one will be your fridge and the other will have EVERYTHING else in your cabin on it. And you'll most likely be sharing that with another person. Nice to have dual voltage hair dryers/curlers with adapter plugs (to european - round, two round plugs 220v). Rechargable batteries for anything that needs it.
Can't think of too many cruise itineraries that don't have a 'civilized' port on the run, so anything you forget or don't want to carry can be purchased within a week or so. I really advise taking everything you'd think you'd need for two weeks.
ALL ships have a crew 'store' called the slop chest. Everything from snacks, sodas, batteries, cd's, DVD rentals, socks, shampoo, razors, detergent, etc, etc - It's will get you through to the time you can get to the Walgreens or Walmart. Some are better stocked than others (my favorite being the RCL Radiance with the Ben & Jerry's pints ;-)
I've also learned to color coordinate my 'off duty' clothes. everything blue and green, mix and match. My uniforms are all black, so everthing 'under' is also. Make for an easy one load laundry wash.
If you can - try to get ahold of someone onboard you ship to find out what you "really" need. You might be spending more time in a company provided uniform than you think - so it's really OK to be seen in that same outfiit the whole time ;-) EVERYONE else is too!!!! . . .they know better
. If you're cruise staff - one formal outfit, on 'smart casual' outfit, the rest is unforms and that's your tradition 7 day cruise!
I think there's been a couple other theads on this topic in the past couple years - if i find them, i'll bump them