In my experience, I've found the most use out of 2 or 3 power supplies, and at least 2, usually 4 DMM's. This is
because I want to see voltage and current both at the input of a module/device under test and at the output.
A minimum 2 channel scope, and 4 if you can afford it. After that, you'll likely not need to buy a scope again, for a
very long time.
A basic function generator is necessary for design/debug. I wish I had more than 1, or a 2-channel unit. As it turns out,
I often have to breadboard up a simple oscillator (or 2) when I need more than my single channel function generator can
provide.
I haven't had much need for a frequency counter, as I don't do much RF work, but I have used a basic frequency
counter done in VHDL, flashed into an FPGA development board, to verify those oscillators that I end up having to build,
above. Or I use the counter in the scope, depending on whether or not the scope channels are busy or not.
I own a USB logic analyzer, the LogicPort LA1034. Really great instrument for seeing bus signals in the digital world.
It also has a built in frequency counter.
I want more cables, banana plug/jack type for power, more cables with smd clips (lots!), etc. So don't underestimate
the value of lots of cables and clips. I wish I had more than I have. SMD and post grippers are far, far better than
alligator clips. I have too many alligator clips and not enough smd/post grippers.
Good luck with your lab build and have fun!