So, its the time of year where I can afford a graphics upgrade, woohoo!
I need honest advice with regards to two cards, the Nvidia GTX 580 3GB, which is in my sights, and the Radeon HD5870 1GB which is in my rig.
First of all, what I want it for:
Primarily Skyrim, BF3 and other modern 3D games. Also, I've been using Photoshop for ages and have been really wanting to get around to learning 3D modelling too, but I never do. Anyway, the 3D art is something to take into consideration.
My current rig:
i5 2500k OC to 4.5Ghz (stable)
Radeon HD5870
8GB RAM (2 x 4GB Corsair Vengeance PC3-12800)
Screen Resolution: 1920x1080
Corsair HDX 620watt power supply (in reviews it was found to supply more power than most 800w power supplies which is why I bought it).
How I want to play Skyrim: 1920x1080, 2xSupersample AA (at least), HD texture mods, FXAA Injector mod or other injector mod, Ultra Settings, uGrids 7 or more
How Skyrim currently performs on my rig at those settings: Indoors 45-60FPS, outdoors 24-40FPS (mostly low 30s, often dipping into 20s)
Other things to keep in mind: I dislike CCC
What I really want to know is, will the GTX 580 fulfill my needs? Is there anyone here who can comment having used the card, or even having used both of these cards? Also, is now the wrong time to buy an Nvidia, is the 600 series imminent? Is my powersupply good enough for a GTX 580 3GB?
I understand the Radeon 7970 (i think thats its name, the new one) far out performs the GTX 580, but to be honest, I want out of this CCC.
My main concern is that I have actually heard that the 5870 is faster than some respects than the GTX580... is this true? Is it worth an upgrade, or is the performance I've got pretty much what I'm stuck with

Edit: I have looked around at various sites, I'm not being lazy here, but I want to hear from you guys because its nicer to hear from people with experience of using the cards in the situation I would rather than reading a review.