It really depends on what video solution you intend to use. You didn't mention a specific video card, but since you did say you wanted to use your machine for gaming, I figure that you probably will be buying a video card as well. Or not?
Well, anyway, the integrated video on the nForce420 is most likely not the best video solution for you, considering that it is about as fast as a GeForce2 MX200 - not a gamer's board. BUT if you ARE planning to use the onboard video only, then I guess the MSI could be the board for you. Although, recently I have been pretty biased towards ASUS and their motherboards. I don't remember the details about their 420/220 based boards, but I am sure they are great products.
If you are thinking of buying a graphics card such as a GeForce or a Radeon, then you should probably get a motherboard built around the 415 chipset, which does not have the built-in graphics, but apart from that it has the exact same feature list as the 420 chipset. So, if you fancy an nForce415 board, there are really only two choices for you.
One would be the NV7-133R from Abit. This board has a full implementation of the audio functions of the nForce chipset, which means hardware accelerated 3D audio for games (beats a Creative Live! 5.1 board according to its spec sheet, if I remember well), and 5.1 Dolby Digital Encoded audio output for use with a Dolby Digital amp. It also has USB 2.0, LAN and RAID courtesy of the usual HighPoint controller. Look for some reviews on the internet to find out more about it.
The other choice, and this would be my choice, is the A7N266-C from ASUS. The C is very important, as this letter stands for the 415 chipset. The E models stand for the 420 chipset, and no letter means the 220 chipset (I think). The main reason why I would choose ASUS over Abit is simply the overall stability of their products. While I cannot complain about Abit in this department either, ASUS still IS the king of stability. Also, this ASUS board (the A7N266-C) actually makes use of the thermal diode on the XP chips (they call their technology C.O.P.), which makes it one of the very few boards that have this feature. The ASUS board naturally also makes full use of the nForce's audio capabilities, and they have onboard LAN as an option.
Well, I hope this helps!
How nice it would be if I could tell you to wait for the 615... But alas, nVidia scrapped it.
