Questions about Seasonic x-series

Hi, I'm currently working on my first build but I was wondering if the SeaSonic will fit in in a case that mounts the PSU on the botttom, since the fan is on the bottom. The case I bought is the NZXT M59. I'm also wondering if the 650W will have enough overhead. The current system i have is:

AMD Phenom II X4 955 Black Edition Deneb 3.2GHz
ASUS CuCore Series EAH5770 CuCore/2DI/1GD5 Radeon HD 5770 1GB
GIGABYTE GA-790XTA-UD4 AM3 AMD 790X
ASUS DRW-24B1ST/BLK/B/AS Black SATA 24X DVD Burner
G.SKILL Ripjaws Series 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333
Samsung SpinPoint F3 1TB HDD
Three case fans.

I want to know if I will have enough for an SSD, a 2nd HDD, and maybe Crossfire/SLI in the future. Thanks for the help.