If you have a hood vent, especially if it's a kitchen range hood, you're almost guaranteed to need to replace the fan. Dale M is the only person I've run across who's found a kitchen range hood link that might work as-is for our needs. Since you already have something, the best choices for our needs seem to be squirrel cage fans or the higher quality in-line vent fans manufactured by Fantech, Vortex or CanFan.
When picking a replacement fan, what you need to look for in either type is the cfm you need for your size hood and how high you've mounted it above your work surface, after having accounted for the static pressure losses of your vent ducting. There's no one-size-fits-all because we each tend to customize our hoods to our working preferences, and therefore need to match the fan accordingly. As you decide which fan to pick, be sure you select one where you get the manufacturer's data on how the fan performs not only in free air, but also looking into various levels of static pressure.
One of the best resources I've found for calculating the fan you need, and how much static pressure you may have to account for, is
http://mikeaurelius.wordpress.com/ventilation-primer/
Linda