It depends.
Remaining on F1: Do you have a valid F1 visa stamp that does not expire until Nov 2004? Then, in case you need to travel outside, you can re-enter using that F1 stamp. if not, you would be required to renew your F1 stamp while on OPT, which is generally hard. F1 has some tax benefits. You dont pay social sec tax or medicare, which amounts to about 7.5% of your income. Quite sizable. (There are exceptions; if you have been in the US for > 5 years then you file tax as a US resident, and you pay these taxes, although your employer may not know about this, and might not withhold anyway, but now I am digressing)
If your F1 stamp has expired, then it is better to get onto H1B. So that the next time you travel outside you can get an H1B stamp and re-enter.
So it depends on when your F1 stamp expires, and whether you foresee any need to travel, and of course whether the quota has been reached.