wanger, they are both pretty good sets. What are you wanting to use as sources for this thing? That could to have strong relevance concerning your decision.
I tend to favor the Sony S3000 over the Samsung 53. But the 53 looks nice....Samsung has a history of HDMI troubles it seems like though. The GV42LF is getting good quality control feedback, lots of problem free sets. The 42 inch Vizios are generally considered to be the best of the Vizios as far as PQ is concerned, as well.
I own the GV42LF and I love it, very impressed by its performance and features.
If this is your first flat panel HDTV, you will probably be thrilled with either one.
Vizio VP322 Plasma / Vizio GV42LF LCD / Denon 2200 Silicon Image DVD / Panasonic S97 Faroudja Genesis DVD / Oppo 970HD Mediatek DVD / Oppo 983H Anchor Bay DVD / Panasonic LX-600 Laserdisc / Aiwa MX100 Multi-region VCR / JVC S7600 S-VHS / PS2 / Sega Genesis / Nintendo SNES / Roku 2 XS & HD-XR / Realistic STA-90 Reciever / Realistic Minimus 7 / Antennacraft G1483 Hoverman / Belden 7915A RG6 / Channel Master 7777 Titan 2 UHF/VHF / Panasonic AX-200u / Optoma Graywolf 92" / Draper Luma 92"