New Macbook Pro Hardware Questions

I'm looking to buy a new macbook pro, and I had a few questions about hardware, especially the few options available when ordering online.

1. 13” or 15”? What are your thoughts? Are there any pros/cons?
2. What are the benefits of 8GB RAM over 4?
3. As far as hard drive, what is the difference between a
Serial ATA drive or a Solid State drive?

Thanks for ANY help/advice!

Sorry! Made edits and it accidentally posted twice!

Would help if we knew what you are going to be doing with the machine.

13-15" is something only you can answer. For some people the 13" is fine, for others too small. The only reason I would get the 15" model is because it has the option of having a faster CPU and a dedicated card.

If you don't need a dedicated card and don't care about screen sizes then the 13" is for you.

4GB is more than enough for everyday computing. 8GB of ram is overkill for the average PC user. I wouldn't get more than 4GB of ram unless you do a lot of video, music and photography work.

The difference between the two is one has moving parts and the other does not. You pay more for the SSDs as they are newer technology and are faster than the standard HDD, but it comes at a price and you don't get nearly enough storage space to justify the cost.

I just finished the search/selection process that you are doing now, so can offer a few observations...
15" - bulkier and heavier
but, has bigger speakers and higher rez screen

Since I'm not doing gaming, the smaller size and weight of the 13" won me over.

Choices on the 13" boil down to slower or faster processor. Faster costs $300 more, but you only get about a 15% speed improvement. I decided to apply that $300 instead to an SSD drive that can give you a 1000% speed improvement.

Now, I'm just waiting for the cost of the Crucial C300 256gb SSD drives to come down ($450 with shipping now). When it does, I'll put a 750GB (or bigger) where the optical drive is now.