Component video provides for a better, richer picture than S-Video does so if you have a choice go with the former. I'd also stay with the DVD player you have...there's no reason to replace it at this point.
I'm a bit confused, what is the best way to connect my Toshiba SD-3750 DVD player to my new Samsung LN-S3251D LCD HDTV? Should I use S-Video or component video? Or, should I just new a new, relatively inexpensive, DVD player?