We're getting a new kitchen fitted next week and still haven't bought
any lights for under the kitchen wall units. Is there anything I
should be looking out for?

I used the ones supplied by TLC. They're very good and give a nice light
that is bright and easy to cook with. They're also pretty cheap and come in
a wide variety of lengths. I prefer a slightly less yellow tube when cooking
anyway, so the 3400K tri-phosphor suits me perfectly. They certainly don't
make the room cold, though. I've got 4 16W 525mm for under cupboard use and
a single 30W 815mm concealed up the chimney to light up the cooker, which is
installed within.

http://www.tlc-direct.co.uk/Main_Ind...ing/index.html
http://makeashorterlink.com/?X196238D8

Where do you put the switch for turning them on?

Use a dual gang switch shared with the main room light switch by the
entrance door. I haven't installed mine yet, so they're switched with the
understairs cupboard, which isn't quite so convenient!

Christian.