As a budget processor? Impossible to predict. AMD's Phenoms or Intel quads could drop to sub $100 prices inside of a week and that would break the current measuring stick of what is considered best bang-for-buck CPU. Or both AMD and Intel could release a new lineup of cheapo budget processors a month from now or something.
There are budgets and there are budgets. Today, if you have only $25, then a single core Sempron is your best option. If you have $50 or so then low-end dual core from Intel like E2160 or E2180 would be the best choice. If you have around $100, then again more powerful Intel C2D would be the choice, anything from second hand E6xxx's to brand new low-end E8xxx's. And if you must go quad, then a second hand Q6600 is the best option since they can be picked up for around $140-$150 on trade boards.
In my opinion, considering how powerful GPU's are nowadays and how much bandwidth and raw throughput today’s platforms offer, that 5000+ BE CPU stopped being "efficient" the day it was released.