It's the "same language", in that it compiles down to the same machine code, has the same opcodes, etc. On the other hand, if you are using GCC at all, you will probably want to learn AT&T syntax, just because it's the default--no changing compiler options, etc. to get it.
I too cut my teeth on Intel-syntax x86 ASM (on DOS, too) and found it more intuitive initially when switching to C/UNIX. But once you learn AT&T it'll look just as easy.
I wouldn't give it that much thought---it's easy to learn AT&T once you know Intel, and vice-versa. The actual language is much harder to get in your head than the syntax. So by all means just focus on one and then learn the other when it comes up.
