Good ol' K6-x...they kinda sucked in a lot of ways, but they kicked ass in other ways.
1. The 2x-6x multiplier trick
2. The voltage mod trick using resistors, allowing you to use low-voltage K6-2/3 on boards that would support them BIOS-wise but not voltage-wise
3. K6-plus CPU's kicked ass. I can't count the number of times a friend would be over and nearly sh*t his pants cause I had a K63+ 450@600 that would perform just about as well as his P3-600 in games, and beat him in most benchmarks.
4. K6 desktop CPUs that you could use in laptops (esp. K6-+)
Good times...good times.
Yeah they suck now, and yeah thats way too much for any K6 cpu, but they were definately underrated I think.