If you want a shooter I would suggest finding a No4 Mk2. Most of these have fired very few shots if any so the chances of a long service life of abuse and use is minimal.
No 4 Mk1 have more chance of having served in WW2 and possibility of being through a factory repair (this is usually marked with an FTR on the reciever, or FR on Ishapore made rifles. Longbranch rifles will not have this marking though if the rifle has been parkarised instead of a blue finish its a good indication it went through repair and refinishing at the end of the war.
North American made rifles are usually a No4 Mk1* which had the design modified on how to release the bolt. The original design has a push down button that allows you to raise the bolt head and remove the bolt. The Mk1* have a notch on the side of the reciever that you life the bolt head up from.
The advantages of the No4 Mk1 design is a superior peep sight, a heavy free floated barrel and its the strongest of all the Lee Enfield actions. They make excellent rifle and shoot well at distances. I've used my Canadian Longbranch No4 Mk1* from 1943 and my British Fazakerley 1942 Mk4 Mk1 at ranges up to 600 yards with iron sights and a scope. My wife gets rather upset when I use here BSA made No4 Mk1.
The other most common one to find is the NoI MkIII. Notice they had a different naming convention based on latin back then. This is your rifle from before WW1 all the way up until 1942 and even further with colonial forces such as the Australians. Of these I have a Aussie made Lithgow from 1941 and a BSA from 1918. These have classic open sights on them which I do perfer the peep sight on other rifles, but they are rediclously fast and accurate. The speed record on a bolt action rifle is still owned by this rifle. The other cool factor is they have an 18 inch bayonet you can stick on the end and nothing looks so awesome as this.
The No5 Lee Enfield is a shortened and lightened version based on the No4. It has a distinctive cone shape on the end so you don't get blinded from the flash. These are much more expensive and there are alot of fakes around of cut down No4s and No1 (as well as 2as and 2a1s) The fakes were mainly made by american companies in the 1960s. The true No5s only served in the mid to late 40s when they were dropped over reported wandering of the front sight. I only been able to fire a No5 a few times and they have quite a kick to them with heavy ball ammo though they did try and make it easier on the shoulder with a hard rubber butt pad. the fake No5s are about a pound or so heavier and the kick isn't so bad but they have a habit of shooting the cone off the end fifty feet down range.
The Ishapore 2as and 2a1s (the later have a different sight on it only going out to 800 metres instead of 2000 metres). These were made in India in the 1950s and saw a strengthing of the No1 Mk3 rifle with newer alloys to handle the higher pressures of 7.62 nato ammo. Thats probrobly there greatest advantage that its alot easier to go into a shop and find 7.62 nato or .308 winchester than .303 British. They have a different magazines design that can hold 12 rounds instead of the standard 10 due to the smaller size rounds. The 2as and 2a1s are not as refined as the other Lee Enfields however. They are blocky, the finish is less well done but for a $200 rifle they are really well liked by people. You might also come across some Ishapores that have been converted to a single shot .410 shotgun. There were used for riot control and fire the British .410 shell which is shorter than the standard US shell so a number have been reemed out on the US market to handle the 3 inch long shells so you have to be careful when buying one to make sure you can get the right shells.
Other Lee Enfields get progressively rarer and the chances of finding them is equally rarer and more expensive, including No4s converted to 7.62mm nato and designated the L9 series, various sniper rifles such as the No4 Mk1(T) in .303 British which alot of these have been faked over the years and they aren't too hard to make all the way to the super rare L39 target rifle to L42 sniper rifle. Any of the last two would be on my dream list unfortantly they are very rare.
I would recommend any of the No4 rifles, No1 rifles or 2a1s. All make fine rifles and can be found from $100-250 depending on conditions nowadays.