I agree that it's personal preference. What i don't agree about is the claim that AMD is better for allowing old cpus in new boards, but not vice-versa. To use Bulldozer, you must still buy both a new board and a new cpu. Same as Intel.
That is true, with past boards it has been different but this time around things have changed a bit.
But there are many people like myself running an AM3 phenom on an AM2 board with DDR2, i want to increase my ram capacity an speed and i see little point in buying 8GB of DDR2 as i have 4 1GB sticks so they would need to be fully replaced plus this board just does not like me pushing my north bridge so in this specific case an AM3+ board with my current CPU and new ram should help increase performance and give me the ability to get a bulldozer in the future assuming that would be a good choice.
In the case with people running an AM3 CPU on an AM2 board it is easier/cheaper to upgrade in a way that
could (not saying it would) show performance increases while staying with AMD, in that case it's almost like running an i5 on a board for the core 2 quad with DDR2 and skipping the 1156 board to go straight to an 1155 board using the exact same CPU but with DDR3 so i understand from that point of view but an AM3 CPU on an AM3 board being put into an AM3+ board would be more like putting an 1156 i5 on an 1155 board so kind of pointless.
Of course i know none of those Intel based examples would work i was just trying to use the CPU generations and boards as examples as to why people still say it's easier with AMD as there is still some compatibility between boards and CPU's.
Even though no matter what sticking with the same CPU wont give any major performance increase for some it would be the best choice assuming they intended to stick with AMD before knowing how well bulldozer performs and costs.
*edit*
most of what i just said has been pointed out before i posted.