Not to mention that it's a subtle, and very important theme to FFVII.
I don't really see how adding a little floating Aerith in the background could be considered overkill.. (clarification?)
Eh - I just thought that - the website is called The Lifestream.Net and a glittering green graphic that portrays what's come to be very well known in the Final Fantasy fandom (or so I would think) as a visual representation of the Lifestream in the Compilation of FFVII...
Aerith's representation is kind of redundant as well as 'overkill' - I would think the title as well as the graphics would allow anyone to know it's a FFVII fansite. That's all.
It's just a feeling I get see it; there is no discounting Aerith in my comments, just her representation here for the website. Again, if it's what you want, go for it - I just thought to mention my opinions.
I like the work being done, either way - and will most likely use it.