Depends what kind of guy you are IMHO. My top choices would be the X3 or the SmartXX v2. I personaly have the SmartXX. If you like to go the easy route, go for the X3. As stated above, it's a piece of cake to install. If you want an LCD add on, they sell a whole custom front panel that's plug and play. With the Smartxx, you have to solder on the LCD and do some cuts to fit it into the front panel. Xecuter is comming out with an IR addon (once again, plug and play) so you can use your dvd remote to power it on and such. One thing I hate is external switches. The X3 comes with an external bank swith that is pretty ugly. You can upgrade to the pro switch for another 20 bucks or the full front panel (X3CP) for 60. SmartXX's OS lets you chose with bank to load from on power on. Don't get me wrong though, the X3 is a great chip. I believe both SmartXX and X3 (along with others such as Xice) have solderless options. You might want to check with version your Xbox is. If you are planning on buying a new one, it will most likely be a v1.6. They are a bit more tedious to install compared to the older version, but I wouldn't reccomend a solderless adpater for those.
@sygyzy: I believe the harddrive limit originaly was 137GB. Now the only limit to harddrive space is your wallet and the market. Upgrading your dash won't do anything, you need to upgrade the bios you flashed your chip with. I recommend the newest X2 bios. I can't remember which it is off the top of my head though.
If anyone has any questions about any kind of Xbox mods, feel free to PM me, I'll gladly help out as much as I can.
