I am quite happy with the gaslesss Clark welder I have - one or two others on here seem to be quite happy with the Clark stuff too. There are a couple of threads in the forum Tool Section that might help:-
http://www.classicroverforum.com/viewtopic.php?f=37&t=9062,
http://www.classicroverforum.com/viewtopic.php?f=37&t=9062
The only things I would say about the Clark 90EN I have is that it is worth buying a longer "earth" lead and better quality clamp to go with it. Also, the hand-held face mask you get with it is rubbish and you should consider an auto-darkening full face mask. Personally, I would stay away from SIP MIG welders - the wire feed mechanism was rubbish on the one I had. Also, I would be wary of MIGs that have "live" torches - I think these are a bit unsafe. Whatever you get, it's maybe a good idea to go for a MIG that allows you to set quite a low current (very useful if you don't want to blow holes in thin bodywork
).
Off the top of my head, a list of the essentials for welding:-
1. MIG welder (obviously).
2. Large reel of 0.6 or 0.8mm wire.
3. Mask and welders gauntlets.
4. 4.5" angle grinder with wire brush wheels (for prepping weld area) and 40/60 grit flap wheels (much better than grinding wheels for smoothing off weld).
5. Weld-thru primer (allows you to quickly paint parts before welding on).
6. Seam sealer.
7. Thin (0.8mm or 1mm) 4.5" cutting discs (for cutting out old metal and cutting new parts).
8. Some decent tin snips (or nibbler) and assortment of large files.
9. Hammers, vice and and formers for bending/shaping repairs.
10. Can of "Fry Light" or similar cooking oil spray (use it to coat tip and inside of shroud on your torch to stop splatter build up).
11. FIRE EXTINGUISHER - I think some users on this forum and elsewhere have had unpleasant experiences of welding related combustion incidents.