Ahhh now there's a problem. I develop a lot using jquery and would like it to handle that nicely. However, the specs do seem good. Got my eye on a dual core atom mobo on fleabay that's currently at £15. The mobo supports 2 gig ram too which should help the mysql server a bit. As you say, it's a trade off, I have a case waiting with psu, hard drives are knocking about and I'm sure I can rustle up an optical drive (dvd+-r/w) for backups etc. main drive to start will be a 200 gig sata with something bigger later...
The Linux kernal seems to support dual atoms with the crappy intel graphics well, thus me going along this route. I shall investigate the SoC option too, but with plenty of laptops and pc's here it's not a problem to use them for other means leaving this machine I'm building simply as a webserver/fileserver/download box which it will probably be overkill, but compared to this monster, much better performance per watt!