Steve,
The only one of the three I would consider recommending for anyone getting their first machine would be the E-_ _C. It is the most user friendly of the three and it still can be overwhelming if you try to hunt in multitones and conductive sounds. If you get it just stay in ferrous/2-tones to begin with.
However... for your first machine I would recommend something like a Teknetics Omega-8000, a Fisher F-5, or a Garretts AC-250. from what i;ve been hearing i'd push you toward the Omega-8000. It isn't nearly as expensive, it's easy to use, it's light, and some very experienced detectorists are beginningto use it as their "go to" machine.
You may hunt for a month or two and decide that this hobby isn't for you. You may not like sweating like a pig, getting down on your knees a hundred times and bringing home 1.85 in change... There are those days though when you find a great site and begin to make great finds but its not that often for most people. No matter what detector you get you'll find that at first you won't know what is going on and why that nickel turned out to be a pulltab, why that quarter was part of a coke can, why that dime was some other trash... but if you keep at it you'll begin to learn... but you still have to dig to know. In old parks the only good sounding signals are either new clad coins or trash... sometimes a piece of jewelry if you dig a lot of pulltabs and foil. In old parks the good targets just give a hint of being a good signal, they aren't soild and you have to learn to read them... they are partially masked and they are only still there because other people didn't take the time to investigate them. The E-T is good at this but from what I am hearing the O-8000 is also. I ordered an Omega today. I need a lighter machine.
No matter what machine you get you will have to use it for many hours and dig up many, many targets before you become good with it.
Also, you need to get a Lesche digger and something like a "ground shark" shovel. Don't carry a garden shovel into a park or into someone's yard. Never dig all four sides of a plug and when it's hot and dry even digging three sides will leave a brown spot. Always take the junk you dig up with you and never leave a hole anywhere... not even in the woods.
So. If I were you i'd spend a little less on my first machine and grow into something more expensive... give's you something to look fowrard to and really... technology has gotten so good that the 0-8000 may turn out to be all the machine you need if you take the time to really learn it. A friend got one last week and he said it will hit a bullet he has buried in his backyard at 11", the bullet has been buried there for 20+ years. It hits it and IDs it... that is good enough and better than a lot of machines that are more expensive.
Think it over before you jump.
Julien