Macromedia flash player is just used when playing flash vids... sometimes shockwave too, especially if there's some interaction involved. You simply install it and it runs itself.
http://www.macromedia.com/shockwave/download/download.cgi?P1_Prod_Version=ShockwaveFlash&promoid=BIOX
As for CD drives I'm no expert. These days speeds are overrated, they keep upping them even though they're so fast already. Depends also whether you want to read, write, etc. The speeds are usually listed in threes such as 40x/10x/40x, which is the read, rewrite and write speeds respectively. Incidentally you should look for around 40/10/40 and up. But since you ask about the difference between dvd-r and +r, are you actually speaking of DVD-ROM drives?
As for the Dell, I didn't click on your link because I'm no expert on the quality of Dell products - but you could always google it for user reviews