Links to video vs. players

Hi all:

I've been trying to get flash video on my site, but have been running into some problems with the player. Then I tried a direct link and that works fine on my computer.

Question: Is this a viable method (i.e. how common is it for users to have a flash player on their computer?). I'm also considering links to real and windows media. I'm really a newbie at this, and would like to get input before implementing it just in case I'm missing something.

Thanks,