I would say as long as your computer can run what you program it is fine. I am developing on my laptop currently (my desktop is at school). Its actually kind of nice being able to program anywhere, but it does introduce lots more distractions.

Think about the minimum spec you would like your game to run on and then get one of those.

The problem i have is that I'm writing a 2D game that runs very well on my AMD 3.0Ghz + X800 gaming machine, but rather unsurprisingly runs badly on my girlfriends old 800mhz laptop. I've decided to buy a second hand laptop similar to hers just to get the game running at that particular speed, which for me is quite quite slow.

if you want to create the next gen FPS, then you'll need something better.

Cheers - 6

It entirely depends on what you're building.

I could totally see myself building an indie 3D title on my current laptop (Sony SZ-140 with 2 GB of RAM). However, for our large MMO platform at work, we use Dell Pentium D workstations with 10,000 rpm SATA RAID drives.

Here's what I would prioritize to build a large system:

1) 2 GB of RAM or more.

2) 10,000 rpm hard drives, ideally RAID 1, or faster (RAID 0 may actually be slower -- you're seek bound, not througput bound).

3) Fast, ideally dual-core CPU.

4) Graphics card.

Now, pretty much any system is going to be "good enough" for most things you can build on your own, although you may wait longer on full re-builds if you use a large level compiler, lightmapper, or big game engine (size like Irrlicht or nebula2 or larger).

What would be the best computer?
A fast one.

Most non-critical concerns with software development involve your CPU speed.

Mainly, compile time. The slower your computer, the longer you'll wait for your code to compile. Compilers are notoriously slow at compiling C++.

Also, productivity. If your computer is too slow, then your fancy IDE will most likely hinder your productivity. A good amount of RAM will compliment a decent CPU speed.

One thing I'll say I can't live without, is my CD burner. Without it, I run a high risk of losing all my code and work. If you plan on doing any serious software dev, then make sure you have a CD burner.

Hard disk space isn't really a main concern when it comes to software development by itself. As long as it has enough space to store your code and your builds/build files - then a 20GB HD should be fine for software dev. However, if you plan on doing any type of media (audio/video/graphics/games) production, then you'll want one or more decently sized hard drives with good read/write speeds.

Having extra ports (Firewire, USB, etc.), whether you need them immediately or not, is also a good idea.

My vote goes to dual monitors... I dont have them myself but 2 monitors could be great for debugging and running a game at the same time.