Let's face it, Fluxbox isn't that minimalistic. And Metacity's description on freshmeat as being "lightweight" is kind of a joke.
Here's an un-scientific comparison.
| name | version | language | lines of code1 | binary size2 | # of libraries3 |
| metacity | 2.9.2 | C | 49787 | 485048 | 34 |
| fluxbox4 | 0.1.14 | C++ | 20601 | 579596 | 16 |
| openbox | 3.2 | C | 20218 | 206136 | 21 |
| blackbox | 0.70.0beta3 | C++ | 16519 | 474144 | 14 |
| pekwm | 0.1.3 | C++ | 12306 | 298972 | 11 |
| aewm | 1.3.0 | C | 2855 | 28580 | 5 |
| evilwm5 | 0.99.17 | C | 1656 | 20244 | 5 |
| tinywm | 1.1 | C | 56 | 5036 | 4 |
This page is not to be taken too seriously.