I'm looking for a texture pack that looks better, but doesn't affect my FPS too much.

I had one a long time ago, that looked great and didn't affect my FPS much.

Anyone know of any?

Theres some good stuff here. Very low impact if any at all.

http://www.tesnexus.com/downloads/file.php?id=18677

Thats the one i had! Thanks man.

http://planetelderscrolls.gamespy.com/View.php?view=OblivionMods.Detail&id=2701 may also suit your needs, as the replacement normal maps are the same resolution as the default ones, so it increases detail without hurting your framerate, though there's an optional addon that replaces the landscape normal maps with higher resolution versions. Primarily, it reduces the pixelation that can occur in them when viewed up close, but of course may cause a performance hit.

Also, the new normal maps can be used with Vibrant Textures, that's what I'm doing now.

The http://tesnexus.com/downloads/file.php?id=30368 is the only alternative I'm aware of (to Vibrant Textures). That's also zero impact, I mean. You can use "Bomret's Detailed Normal Maps for Vanilla", as linked to above, with Mtgr, just as you can with Vibrant. A different style, is all.