Poll Results

Total votes: 1311

1×2 plates: 658 (50.2%)
1×3 plates: 23 (1.8%)
1×4 plates: 44 (3.4%)
2×2 plates: 207 (15.8%)
2×3 plates: 26 (2.0%)
2×4 plates: 50 (3.8%)
4×4 plates: 179 (13.7%)
Other: 124 (9.5%)

I have to go with the 2×2 plates myself. The 1×2s I can get enough of a bending motion on to split them apart along one of the long edges, then I can insert something sharp into the crack and prise them apart. The 2×2s offer no such simple leverage.