Check the LED UCL DIY As far as I know, there's no good way to retrofit LEDs into your halogen pucks. The DIY should answer everything else.

There is some great info over in the lighting forum if you do a search there. What do you consider expensive? I am also picking out UC lights. I have about 11 linear feet of uppers in 3 sections. For hardwired dimmable LED it's going to cost me about $650. I'm far from an expert on this, but I have asked a lot of questions trying to find a less expensive option. Dimmable is the expensive part. To start you must make sure the product you are looking at is dimmable, not all are. You also need a power supply, and electricity for each area if there is a gap in cabinets, since you are talking hard wired that means wires in the wall to each place and a junction box. You also need a driver, I think those also come dimmable/non-dimmable, and they are expensive. Plus a compatible dimmer, which are also expensive as far as switches go. That's as far as I got researching because by the time I got that far I could already tell the environmental lighting product was less expensive for my project, plus they have been recommended here and have good support (you can send then your plan and they will send you back a plan/parts list). Some products are more inclusive, for example the ones I'm using from environmental lighting has lighting bars that include a driver. A lot depends on the system you are using. If you can't find what you need in the lighting forum, try posting about the specific product you are looking at.

We just had our kitchen remodeled. Our electrician was recommending top-name brands such as Kichler, but we almost fainted when we went shopping for them. We did some checking around and found a nice undercounter LED in 2 sizes - in stock were 18" and 27" - and there's a 10" available for special order. The brand is UTILITECH, made for Lowe's, but checking the back of the box they're distributed by Kichler! We've had them installed for about 4 weeks now and I find that they're my most often used lighting in the kitchen. I have pendants over the island, hi-hats and over the sink halogens - but over and over again I turn on these undercab lights. We love the look and they were inexpensive enough so if and when the technology changes, and we decide to change, we won't have spent a small fortune as the Kichler systems were going to be. Helene

What is being referred to as "Xenon" here is really incandescent bulbs. Smaller incandescent bulbs (like the type found in old-style flashlights for example) have a much lower color temperature, and as a consequence the light typically feels very orange-colored and dull. Bulb designs filled with Xenon gas help compensate for this, to some extent. I can get much more into the technical details if you want, but that is the basics of it. In general though, Xenon will still give off a lower color temperature than halogen, so if you really want a brighter whiter color of light, Xenon is probably not the best option. LED is probably the best option for undercabinet lighting, but can oftentimes be overly pricey. If color rendering is an important consideration, you might want to look into high CRI LED lighting, because under regular LED lighting colors can appear just a little grey-washed or yellowish. This is likely to be even more pricey though. Incandescent bulbs (which includes Xenon and halogen) are just not particularly well suited to undercabinet strip lighting. For one thing, when there are multiple bulbs each with a lower wattage, the color of light is confined to the very warm white color territory. Then there are always bulbs burning out that need to be replaced. There are many different options, and they all carry their own subtle advantages and trade-offs. All undercabinet lighting is kind of overpriced, in my opinion, so unless you are really looking to create a dream kitchen, you might want to consider going without it.