I'd say it's worth it because once the PS4 comes out, the prices for it will drop dramatically after a bit with Sony and retailers trying to get rid of all of them. That and the vast library of PS3 games that will all still be available for purchase for quite some time will tide you over. And I doubt that services like Netflix and Hulu will discontinue service for the PS3 when the PS4 comes out. That and you've got a DVD and Blu-Ray player all in one!
I'm not sure about purchasing PS3 as of now because I guess PS4 will come out soon so once you purchase PS3 today, you will be envy again to others who are already with PS4 so it might be better if you just wait until PS4 to come out and purchase it instead.
No, I'd still tell you to go ahead and buy it. If it's like last time, Sony will have different size hard drives, so you can get the smaller one and save yourself some money. Then there is still the issue of the library, it just won't be that extensive. Above all, if you get one now, you can move the old one to another room to play or just to have as an exclusive Blue Ray player. There are many things that you'll be able to do now and then if you buy the PS3 now.
that depends what you want to use it for if it is for video gaming then you might be too late but if you want to play blue-rays and stuff then go for it they are very cheap right now and its a great time.
No, it's fine, just buy it! I promise you, it will be a worthwhile purchase. When the PS4 comes out, you can still hold off for about a year, sell of the PS3, and get it at a cheaper price than what it initially retails at. Trust me on this, sometimes good things come to those who wait - and in the console corner, it would definitely be better to grab that PS3 ASAP, then trade it in for that PS4.