Originally Posted by GuitarBizarre

You have to remember that using a bigger speaker won't necessarily make your sound good. It'll reproduce lower frequencies in greater amounts, but the larger the cone, the more you lose fine control over it, which may well hurt your midrange performance, which is where the guitars voice really is.

Make sure to tune the cab if you can. A cab that is too big will produce too much low end and you'll end up stepping all over the bass in a mix.

(BTW, As a note, I really can't stand it when people assume that more bass is the answer to all their problems. If you listen to any well produced record, you'll find that even heavy bands use a much more high and mid frequency based sound than you'd think, because too much bass from the guitars just turns everything into mud.)