The short answer to your question is that the form of will you suggest would be perfectly valid as long as your husband ensured that there were two witnesses to his signature. (It would, however, be easier to obtain probate if he also named the executors of his estate).
However, I used to be managing director of a will-writing company. If someone asked me to prepare a very simple will, along the lines you suggest, my first question would be "What happens if both you and your wife die in the same accident?". That's just one example of several things which you really need to consider before attempting to draft a will (whether with or without professional help).
I've previously posted more detail about this subject, here:
http://www.theanswerbank.co.uk/Money_and_Finan ce/Question152656.html
However you go about writing a will (even if you use a solicitor), I strongly recommend reading this book first:
http://www.amazon.co.uk/exec/obidos/ASIN/08520 29713/qid=1147048543/sr=8-1/ref=sr_8_xs_ap_i1_ xgl/026-3880441-3552447
(You probably won't need to buy it. Most libraries stock it or can order it for you).
Chris