The portal seems to be expanded beyond the resolution I'm using (1024x768) which is resulting in some uneeded width scrolling. I'm almost sure this is down to the image (world map) that is causing this. In anycase it's something I would rectify as it can really get annoying if anyone person is spending time on your frontpage.
Overall I like the style, There could be improvemnts with the images and I would advise that you search for something that looks a little better, more eyecandy but professional looking and sleek at the same time.
I like the way you have developed the navbar menu. The curviness and logo intergration looks very nice and more importantly uncluttered. Noting your logo, I think your right about it that you should eventually get it changed. By adding an image (consistent with your theme) the appropriate font and a nice slogan will defentitely give this a nice desrving facelift.
Another pet hate is alignment of text within the graphics and I noticed the text on the buttons are off to the right. Possibly center them?
A couple of minor changes (which is a 30 minute job) would give this nice style a better look imo.
Nice work regardless.