I have Macbook Late 2007 with 1.83GHz C2D, 2 gigs of ram and 160gb hard disk. Graphics are handled by Intel GMA 950. Right now it has Snow Leopard which works OK, just recently installed. According to Wikipedia Snow Leopard still receives security fixes but is this true? I don't know what features in Lion I would need but the state of support worries me a bit, then again I have used Tiger and Leopard in my PPC Macs without noticing any problems. Also this Mac is lowest end of machines which fulfils official system requirements so it might be sluggish?