Yeah, lots of people may consider it a silly move because Blu-Ray and HD-DVD are still at it and the PS3 is overpriced for a console, but:
1) My PS2 was one of the original batch and still had the flaw that made it not play DVDs and some games very well (had to try dozens of times to get them to work). (Apparently many people were able to send their systems in for free repairs, but mine worked well enough that I never bothered.) So I wanted something new that could play all my PlayStation and PlayStation 2 games.
2) I wanted something that could play DVDs
3) I like the idea of getting a Blu-Ray player below cost (PS3 is one of the cheapest if not the cheapest Blu-Ray player available because game systems are generally sold at a loss because of the profit that will be made on the system's games).
4) I had a gift card from work for my 10 year service anniversary that covered the whole cost of a PS3 and then some, so it didn't feel like it was really coming out of my pocket anyway.
Oh yeah and:
5) Durnurd gave me "permission" to get one when he discovered that there was a new Lemmings game available for it.
Some extra bonuses I got that I wasn't expecting:
1) I really like the ability to download game demos for free over wireless internet. I used to wait years for demo discs on the PS2... they came so rarely.
2) Slots for camera memory cards
3) Ability to browse the web and watch videos over the internet from the PS3 (my computer isn't near the room where the projector is like the PS3 is).
4) Forgot about how cool the wireless controller would be... the old one barely reached where I wanted to sit. The new one works great, and recharges when it's plugged in to the USB cable.