I've lived around and In Penrith since I moved to Sydney. I wouldn't pay much attention to RBDouche25. He's probably driven through the riff once or twice and just heard all the jokes that one makes about the suburb to their west. (We even do it to Mountain People )
Penrith's great. There's a fair amount of stuff to do, the people are friendly enough, you don't often have to deal with shit traffic if you need to get somewhere, there's a great car scene (thursday nights), decent night life, nice scenery (river, glenbrook park + mountains).
Penrith YMCA is a great gym. it's $26 a fortnight and packed full of great equipment and there's almost 0 knobheads who go there.
As you can see from the lists above there's plenty to do and it's a nice area.
Only drawbacks of Penrith... It's an effort to pull an all nighter in city due to transport (unless u get a hotel) and... By the time you drive an hour to beach in your air con car you don't feel like going to the beach ) They're seriously the only 2 negetives I can think of.
If you want more info or details about stuff, send me a message. Glad to help. WOW!! RB was right... We're not to friendly out here are we