Ok, here's my current favorite indie engines:
www.unity3d.com for the Mac.
www.beyondvirtual.com for the PC.
Both feature elegant, nearly transparent art pipelines, which is what attracted me to them. No special level geometry, no BSP brushes, etc. etc. In the case of Unity, it supports Maya, Cinema 4D and Cheetah files directly, in addition to 3DS, OBJ and FBX.
Beyond Virtual is in an earlier beta stage of development. It was designed around Lightwave, but it imports FBX, 3DS and OBJ files as well. The best thing about BV is that there is a Bronze version that is absolutely free.