Get the PSX version of MGS because I think it's better than the Gamecube version in terms of cut-scenes and dialog. With the Gamecube version, they brought back the actors to redo the dialog, but I feel that a lot of emotion was lost. Also, the cutscenes in the Gamecube remake were like watching the Matrix and I really hated watching them.
For MGS2 and MGS3, find MGS2: Substance and MGS3: Subsistance because these include the game as well as extra content (Metal Gear 1 and 2 in Subsistance) and will offer an overall better experience.
As Twestern was saying, there is the Metal Gear Solid: Essential Collection that should include MGS, MGS2: Substance, and MGS3: Subsistance and as stated above, should then also include Metal Gear 1 and 2 for only $30.
http://www.gamestop.com/Catalog/ProductDetails.aspx?sku=281885
