I agree with Western, few things are universal. If you are wanting to learn software - I would aim for more advanced stuff if you have the time and the background. Of the things on the list, I'd say if you can learn Matlab and R/S-Plus well, they will probably offer you the most in terms of flexibility and you'd be able to pick up most other software like it was nothing. That said, the learning curve for both is MUCH steeper than average and will take months to become properly grounded in, and years to achieve anything approaching on "expert" use, whereas you could train a monkey to have a basic knowledge of SPSS in about a day.
I've been delving into Matlab more lately, and it is actually making me wish I had doubled in either engineering or math. I'm just starting in on it, but its pretty clear I'm nowhere near even being "functional" in it. That said, many faculty won't even know what Matlab is, let alone how to use it, so its not exactly a pre-requisite unless you want to work with Richie Davidson or a handful of other folks. Psychologists tend to be disturbingly low-tech, and I never cease to be amazed at how afraid many people are of actually learning technology in any real way, so good for you if you are willing to take it on. If you can do so effectively, you will probably be far less likely to publish stuff that is analyzed wrong, and catch all kinds of other errors that I'm sure end up in the literature with great regularity due to people not bothering to learn about computers, and running studies/analyses when they don't actually know what they are doing (i.e. producing an output is a necessary, but not sufficient step in the analysis actually WORKING...something that I think is often forgotten). Of course, that can be bad for your career to (ignorance is bliss and all...).
One piece of advice though...while I think it is great to learn these things, don't let yourself become the "computer guy". Its easy to end up shouldering responsibility for other people's crap when that happens because you may be the only person capable of doing it, and it can be overwhelming (speaking from experience right now).
