It would seem that we need a set of criteria to go by - something like the Military Channel does with their "Top Tens" except that we can probably leave out "Fear Factor" - unlikely that a kit that is so poorly engineered that you don't want to build it should be in the top ten (I guess that eliminates Aurora's Bonhomme Richard).
My first cut at the criteria would include (most important first):
1. Scale fidelity (the appearance and proportions of the kit should be identical to the real ship)
2. Detail and Completeness (the kit should have be highly detailed and include everything that you need, aftermarket PE should not be needed)
3. Length of production and availability (for example Revell's 1:96 USS Constitution and 1:570 Queen Mary have been around for a long time and are in the catalog year after year)
4. Innovation (did the kit offer some really innovative features or it was it groundbreaking in some way, for example the Revell 1:192 USS Constitution was highly detailed for its time)
5. Price (how much do you get for your money, a 10 being under $15, 9 under $20, 8 under $25, etc.)
If we try an example, say Revell's 1:84 NYFD Firefighter, using a scale of 1 to 10
1. Scale Fidelity: 10
2. Detail and Completeness: 10
3. Length of production and availability: 3 (the kit has been around for a long time, but is not in the catalog very often)
4. Innovation: 3, it's a nice kit, a unique model, and originally came with brass plated parts, but nothing earthshaking)
5. Price: 8 (the kit has always been affordable, i.e., under $25)
So that would give the Firefighter a score of 34 out of 50 or about 68%
Anyone want to give another kit a try?