lude2S

Alright, so i finally picked up the Eclipse 3434 headunit and i am loving it. Now i wanna upgrade the the speakers. Just looking for a little advice on which to go with. I've been doing alot of browsing lately and have been focusing in on the Boston Accoustic Pro60's, Diamond Audio S600's, JL XR components, or maybe a nice set of Focals or Eclipse. Not looking to spend crazy money, but willing to spend a decent buck to get quality speakers. Sort of thinking of spending about $350-400. First off i was wondering about the difference between the Silk and Aluminum tweeters in the Diamond Audio S600's.
For amps i am not quite sure. I have been looking at the Diamond Audio D5 series amps, or possibly Soundstage Tarancula series. Am planning to add a nice 10" sub at a later date. Would it be better to buy a larger amp to run everything off of or should i buy two smaller amps?? Any insight would be great.