MCSE 2000 or XP which one?

I’m a MCSE in NT4 and want to upgarde my certification but don’t know whether to go for MCSE2000 or MCSE XP. Can anyone advise me which one will be the most used by companies in the future?…My company has started the project of rolling out XP across the board..but I’m also thinking about if I change companies will I be more likely to use XP or 2000.