There are four North American variants, but all came with five CD-ROM discs, a manual, and Silent Hill 3 Official Soundtrack CD. All six discs came in generic paper sleeves, but the sleeves are black or white depending on which variant.
There are two box variants, box 1 and box 2. The artwork is slightly different, but the boxes appear to be the same size. There are four disc variants (including the soundtrack), disc set 1, set 2a, set 2b, and set 3. Disc sets 1 and 2a came with box 1, while sets 2b and 3 came with box 2. Disc set 2a and set 2b may be identical, or just very similar. Either way, in total there are four possible combinations of boxes and discs.
The order of release is unknown, the given variant numbers are assigned only for practical reasons.
This page is for box 1, disc set 2a, shortened to variant 1-2a.
On this variant, the artwork on the front of the box is cut right above Heather's hair. According to the copyright text on the back cover, the game was distributed by Vivendi Universal Games. On the bottom side of the box the barcode is on the left side. The box is, as far as I can see, identical to the box included with variant 1-1.
All six discs have a thin ring of missing artwork around the spindle hole, about 1 cm from the hole. The rings of missing artwork on variant 1-1 discs are thicker. Also note the placement of the copyright text on the soundtrack CD when comparing to other variants.
All the discs came in black paper sleeves.
The manuals included with box 1 and box 2 are also different. The manual included with box 1 cuts the artwork right through the hair. There may be a slight difference between the manuals included with variants 1-1 and 1-2b. It seems manual 1-2a shows a little more of the artwork below the Konami logo.
The soundtrack included with the PS2 edition is yet another soundtrack variant. The easiest way to tell them apart is by looking at the placement of the copyright text on the discs.
1. Front
2. Back
3. Bottom
4. Manual front
5. Manual back
6. Disc 1
7. Disc 2
8. Disc 3
9. Disc 4
10. Disc 5
11. Soundtrack CD
12. Variant comparison guide