Perl or Python. I'd look into Perl. That's how I got my start.
Perl is awesome since you can play and figure how to manipulate files or perhaps get some shit off a website. I did that for about a year and then bought Jeffry Friedl's 'Mastering Regular Expressions' which I read for about 6 months. I soon became pretty proficient at regular expressions although some extended regexes still throw me off and I have to stare at them for a while to figure them out.
Anyway, when I started using Perl, my job requirement didn't really utilize it. But when I started looking for a job, it came in really handy. My current job which requires knowledge in C/C++ was something that I didn't have at the time I got this job. During my interview I made that known but the folks at my company weren't worried about that since they knew that if I knew Perl, I could get up to speed in C in no time. And here I am 4.5 years later.