There are dairy free alternatives, but it's certainly not butter!

You may be familiar with the advertising slogan for a current alternative to butter: 'I can't believe it's not butter'. Unfortunately, I don't think there's a true alternative to butter in dairy free land. It's very difficult to replicate the true flavour of dairy products. However, I have found a spread that replaces margarine quite nicely. The one I use is produced by Pure dairy free. They have produced three different versions: Soya, Sunflower and Olive, all of which are are associated with certain health benefits. Their website provides more information and some helpful recipes to try, but here are a few of my personal thoughts about their products:

Soya

The soya version isn't any use to me, due to my problems with soya. I did try a bit, to see if my body would cope with it (it didn't), and it seemed to taste OK. It is the spread of choice for supermarkets - if they only have room for one dairy free margarine, they seem to stock this version, by default - which is rather annoying for those of us who need to avoid soya!

Olive

The Olive version is alright, but I thought it produced slightly greasier results, when baking. 

Sunflower

My favourite version is sunflower, which I have found to be very versatile - good on bread and toast, I've also used it for making scrambled egg and cakes, with excellent results. I have to admit, I thought that it might have some unpleasant after taste, but I haven't noticed any. The other good thing about sunflower is that it contains vitamin D, which your body needs to absorb calcium.

Update
Since I wrote this post other dairy free margarines (usually made with sunflower) have seemingly sprung out of the woodwork! Vitalite's version is available in many places, Sainsbury's also sell one called 'Tomor' in the Kosher section of their chiller cabinets and most supermarkets now seem to be producing their own dairy free brand - from M&S to Aldi! Now we have choice!!

Update 2015:
Look out also for Koko's new margarine, which is coconut based. It is currently sold via Waitrose.

Here's what to look out for!

Update 2016:

Now Flora have entered the dairy free fray by bringing out their own dairy free version. Watch out though, as the packaging is very similar to it's Original margarine! I also hear that its made on the same lines as other products containing milk, so if you're really sensitive to dairy, it may be best to avoid!