Should the United Kingdom approve the treaty establishing a
Constitution for the European Union?

I doubt that we will have a chance to approve or disapprove.
- ie: I reckon they will weasel out of a referendum - somehow

The problem with the EU gig is that we are surrendering legislative
power to a bunch that we can never vote out.

There is little harm in a free trade area (although the EEC was a
protectionist zone) but this steady transfer of power(s) to Brussels
has far reaching effects.

I cringe every time 'Human Rights' and 'EU directive' is mentioned.

NO, say I, an American living in Germany.
I could go on and on the subject, having read the draft in both languages.
My primary complaint is the lack of democracy, that the European
Parliament virtually does not have the right to initiate laws,
something only the Commission may do.  As we know from the past, the
people in the Commission think up all sorts of good thing that should
be regulated (remember the size and curve of cucumbers, or better
tractor seats?), and have a strong hold on the information to support
their ideas, while having no responsibility for what implementation
will cost.
Right now, the problem that the acceptable level of micro-particles
has been reduced, on the assumption that the new level can be achieved
just by putting exhaust filters on diesel vehicles. Bang!  By the end
of the year, every major town will have breached the new level, but
now studies are showing that most of the microparticles are stirred up
tire-rubbing; in another study, that a lot of them are from
non-vehicle related sources.
  
A constitution should provide for a much better balance of power
between the representatives of the voters, the administration, and the
court.

I'll stop.  Oh, but the constitution does provide that a country
secede from the Union.  Maybe the UK could consider that before it
chooses to implement the Euro.

THIS QUESTION SHOULD BE OF BURNING INTEREST TO ALL EU RESIDENTS,
but no one seems to care.
Jacque Chirac held a TV discussion Thursday night with 83
"hand-picked" young people to drum up support for the upcoming
referendum in France (55% against according to polls), and almost fell
on his face, responding to a guestion about what its advantages would
be by saying that it wasn't the time (or appropriate?) to talk about
that now.
The politicians don't know themselves, probably because there aren't
any, otherwise they would have been pointed out.  But like much in EU
politics, the idea of a having a constitution just took its course. 
Once the conference to write it was established, and the thing was
drafted, no one was willing to come out and lambast it.

But, thanks Rai130-ga for raising the question.