topic says it all

Personally I felt the first game was better. I say play through the original first, it still holds up extremely well.

I have had a sealed copy of Dead Space 2 for almost a month because I haven't bothered yet to play the first one, that should answer your question

Honestly, and this is obviously just a personal input, but in my humble opinion the first one is actually better than the second, so yes, by all means, play the first one before jumping into the sequel! :)