I will echo most of what has already been said here.

The newer generation of NiMH that discharge slowly are the way to go,
in my opinion - even if the overall capacity is lower. Get a good
charger, one that can charge at various rates. Charge at the slowest
rate you can, given the time you have. Do a discharge
periodically....I do one every 4th charging cycle.

I have been really impressed with the Kodak branded NiMHs that have
the low discharge chemistry.

I only use alkalines for devices that I use very infrequently or have
a super low discharge rate (like a quartz clock). Sometimes you may
have a device that simply needs the extra punch that alkalines can
give...as they are rated at 1.5 volts. Although I will say, even
though NiMHs are rated at 1.20-1.25 volts, I reguarly see them charge
up to 1.4 volts or more.

On my high use devices, I simply have gotten into the habit of weekly
replacement with a freshly charged set. It's easy and economical.