Well, it depends on the size of the monitor. For example, on my 19" monitor it is really better to run LFS on a bigger resolution than 1024*768 , because on a big monitor U will see a huge difference between 800*600 with AA&AF and 1600*1200 with no AA&AF. For taking screenshots, it is different, because in my situation, i will see the picture taken @ 1600*1200 with no AA&AF on a 1024*768 res desktop with all the jagged lines, but actually U wouldn't notice it ingame , but U will see the pic taken @800*600 with AA&AF on a 1024*768 res desktop with no jagged lines, and U will think, hey, that looks good, but ingame, it isn't so good , imho
(it is hard to say what i really mean,pls forgive me, if it isn't understandable , i need to learn english more :o )