For your situation I would recomend looking in the Newbie Forums
first. Then when posting read the description of the actual forum below the forum title. I reason i say that is because this has nothing to do with this forum. You probably didnt know that though because you probably saw the forum that said hardware modding and posted here. There are forums specifically for modchips and if you look there you will find more info than you want.
As far as the best modchip goes, all that is is a matter of opinion. All a modchip basically does is let you run a hacked MS bios. Sure some later modchips have added features but most people dont really use the added features that often if never.
The two modchips I would recomend are the Xecuter 3 and the Xenium.
Now after saying all that you really need to do A LOT of reading about the different chips.