Zeldascorn, do take into consideration that getting a Globe unit also means that the iphone is a locked unit. Unlike other European countries, Philippine carriers do not unlock iphones after the 2-year lock period. But if you're planning on sticking with Globe after your lock-in period, I guess that wouldn't be a problem anyway.
Like what Apple did with the 1st gen iphone, there is a large probabilility that the iphone 3G will be phased out soon - i.e. discontinued support for newer features added to new firmware releases - once the rumored 4th gen iphone (keeping fingers crossed) comes out later this year. If you need to get it right now right now, getting a 3GS would be a better choice to be more current with Apple's product line and their future firmware support plans.
However, if you're a simple user who doesn't really need to be updated with each new firmware, an iphone 3G would be a more economical/practical choice though. So it really depends on what kind of user you are.
