I have no under cabinet lighting now. I am very excited about having LED under cab lighting in this renovation. I have been looking at the Kirchler lights which are mounted to the front of the cabinets. The longest box is 18", is that big enough for a 30" cabinet or do I need to link a 6" with it to make it a total of 24"?

I would try to make the longest possible continuous run as possible to minimize shadow zones.

Look at other vendors too. There is the LED UCL DIY thread on this forum.

I used the longest possible light bars that would fit because I did not want "breaks" in the lights. For a 33" cabinet, I linked a 24" and a 6" bar, and then it was a tight squeeze to place the hole where the wire had to go up thru the cabinet, or thru the bridge to the other cabinet. I do have one 36" cabinet that I still just used 30" of lights, but there is a dimmer switch on the end. For 15" cabs I used 12" lights.

The on/off/dimmer switch is 2", so I allowed for those at the end of each run.I got my lights thru environmentallights.com and absolutely love them!

Here is a link that might be useful: the dimmer switch I used

I'm writing to share a trick for using flexible LED strips for under-cabinet lighting. The problem I was having is that you see reflection of every single LED light on the counter if you have a polished stone countertop. The idea is to create a rail to mount to the under-cabinet that angles the light toward the backslash and slightly up. It creates nice even light and eliminates the reflection of individual LEDs on the countertop...

I had my local heating-duct supply store bend a strip of galvanized sheet metal: long enough for the run of lights by 2-1/2 inches wide. This is bent along its length at a 60 degree angle - with 1.5' (3.5cm) on one side and 5/8' (1.6cm) on the other. (The profile looks like a check mark.) Spray paint the whole thing flat black-to absorb reflections further. The 1.5' part is attached horizontally to under-cabinet - with the 5/8' part furthest from the back-splash and about 9 inches from the backsplash. The LED light strip is attached to the 5/8' part so it faces the backsplash (and slightly up). Looks a something like this in profile installed:
_____
\*

I used this product http://www.ledlightsworld.com/smd-3528-flexible-led-strips-300-leds-p-90.html warm light (3000-3500), waterproof surface injection (IP65), background white - comes with 3M adhesive on back. They ship express from China, and I found them to be reliable and responsive. They also have a range of UL-listed transformers - (it's a 12V DC application) and connectors. If you want tons of light they sell a strip with twice the LED density (600/5 meter reel)-but also twice the price. I found the the 300 to be plenty of usable light in an already well-lit kitchen.

Here is a link that might be useful: My supplier

ctpete, can you post a picture of your installation please?