"Help me find a great kit that is fun to build."  Then you want either the Tamiya Pz III ausf L(kit 35215) or the Tamiya Pz III ausf N (Kit 35290).

All the DML ones are very complex and require a very motivated builder.  Either Tamiya kit will be easy to find and a breeze to build accurately and in a timely manner.  

Here's a nice review of the ausf N kit:

http://www.perthmilitarymodelling.com/reviews/vehicles/tamiya/tam35290.html

Don't get the ancient, early 1970s Tamiya Pz III kits -- I don't mean THOSE.

I'll second Roy. I have both of those Tamiya kit, I am about to start the N. Tamiya are really nice kits and a real pleasure to build. Dragon are very nicely detailed, but are not always easy. It would really depend on how much experience you have in building armour and how much hair your happy to pull out.

Thanks both of you for your answers.

So I guess Dragon's reputation really precedes them ... so the Tamiya Ausf L is the way to go then.

And what about other manufacturers ? So far I have a love / hate relationship with Italeri ... some of their kits are a joy to build but others are quite near the garbage bin ... 

On a side note, can any of you recommend me a " beginner " Dragon kit (if such a thing exists) ?

Not that the Dragon Panzer III's have a bad reputation,they are excellent kits,and I have enjoyed a couple of them,just more complex,but also more detailed.But you can't go wrong with Tamiya ease of assembly.

The t5hing with Dragon kits is that the instructions are not always easy to follow and at times they give you 3 parts when other companies will give you one. This means they are very detailed, sometimes overly so.

But on saying all that, my current build, a Dragon panther, has been a real pleasure. All the companies have good and bad builds, you really have to take it on a kit by kit bases. My favourite for armour are Tamiya, AFV and Dragon. But while there are many companies that produce good and bad kits, I would say there are few that should be avoided completely.

I just finished this Dragon III J initial and it was a lovely kit. Sure some tiny parts but they look all that when they are in place.

Panzer III ausf J with DAK Infantry by Gadgetworks3D, on Flickr

Yes, any of the newer Dragon smart kits would work well. They have less parts, but still offer great detail. They have everything you need like PE screens. Tamiya's L doesn't.

The Dragon kits are not much more tougher to build than the Tamiya kits.  They do have a decent amont of PE parts but these are usually large like engine deck screens.  But the tools have molded on clamps which is definitely easier than the separate tool clamps.  The hardest part would be the Magic Tracks which take a little patience but aren't difficult to assemble at all.

I personally prefer Dragon kits because you get more for you $$ compared to the prices of Tamiya kits.  Newer moldings, better selection, more detail and more marking options usually.  

Now their "Super Kits" are a whole different animal...

I've built that one too, was a real pleasure to build.

I built the old Dragon Imperial Series Panzer III H a couple uears ago. It was not overly challenging, and if you do not mind indy link tracks goes together easily enough. I do recall there was an issue about the idler wheels parts and instructions, but other than that was pretty much a trouble free build.