Now this question is impossible to answer satisfactorily. What do we base our answer on? Victory/Loss ratios are inconslusive because they are only
valid in large numbers; Sales as well because sales are as much influenced by politics as by technical aspects. All in all, no single statistic could
be chosen to evaluate such a broad question; one has to look at the complete picture, above and beyond the simple performance tables.
My personal choice would be the Bf 109, a horribly uncomfortable, short ranged, very characteristic if not to say picky and unforgiving airplane that
somehow still enabled the Luftwaffe to resist the enemy for a long time.
It is possibly the longest-lasting frontline fighter of the WW2 era, from 1937 into the early 60s (spanish service). It was the most-built model of
any fighter, over 30.000 pieces, although there never were, on average, more than 1000 flyable aircraft in the inventory at any time in the war - and
that although it took considerable less time to manufacture than many of its allied counterparts, and although the Luftwaffe had many other promising
designs at hand.
And despite its shortcomings it also helped produce an unbelievable list of fighter aces - undeniably experts that in large parts resisted to fly any
other aircraft and that should count for something. Hard data however is very hard to find because of lost and lacking documentation, so I don´t have
any performance tables at hand.
I however have some "quoted quotes", take them for what they´re worth:

"109s kill ratio."
- According to Edward Sims' "The Fighter Pilots", the Luftwaffe claimed about 70000 victories, for the loss of 8500 pilots KIA, 2700 POW and 9100
wounded in action, for a total of ca. 20000 losses. Not knowing the real numbers, we could speculate there were another 20000 pilots who bailed out
OK, that we arrive at a 70000:40000 kill ratio for the Luftwaffe, or 1.75:1. That's not bad at all considering the catastrophic finale.
- From April 1941 to November 1942, the Luftwaffe scored 1294 confirmed victories for about 200 Me 109 lost in combat. During this period, the
Luftwaffe almost exclusively used the Me 109F. They identified their victims as 709 Tomahawks, 304 Hurricanes and 119 Spitfires, plus
others/unidentified. That's a ratio of about 6.5:1. (location missing, but looks like North African campaign. Author suggests that these numbers
should still be taken with a grain of salt, I have no clue if these are post war verified numbers or wartime claims)
[edit on 18/5/2008 by Lonestar24]