I use a handheld lightmeter with the Lubitel, when using the Lensbaby, and with the D70 in situations when incident metering will be more accurate.

Seeking advice from a knowledgeable friend, he recommended the Weston Master V. Despite being over 50 years old, they have a reputation for maintaining their accuracy. (The meter too ...)

The advantage of Weston meters is that they are selenium based, so require no batteries, and with the invacone (the white cone on the left) can measure incident light - see below.

You can pick them up from secondhand camera dealers and on ebay for somewhere in the £25-50 range. Make sure the invacone is included - this came with the meter when new, but some people cheekily offer it as an optional extra.

If you want to check the accuracy of the meter, or ask the seller to, hold it about a foot from a bare 60-watt bulb in an otherwise darkened room. The reading should be around 7-8, though it may go to 9-10 if carrying out the test in the smallest room (the effect of white walls close to the light).