Forge upgrades against different races.

OK. So your micro and macro are decent, your good at getting a nearly maxed out army early but you are a bit unsure of what to spend your extra vespian gas and minerals on.

Lets take a look at which upgrades you would want to tweak your units with for each race.
*Note two forges are usually common for a two based toss.*

Upgrades for:

Protoss vs Protoss - Try and balance 1 1 1 -> 2-2-2 > 3-3-3 > Max.

If you are going more offencive, micro based attacks increase your attack first.
If you are teching fast than balance your defence and offence out a little more.

Protoss vs Terran - Ground armour is really important, if you can get 0-3-0 before anything but since you'll probably have two forges do attack and defence simultaneously, at one base one forge get defence first though. Shields are good but I tend to upgrade them dead last because all it takes is an EMP and not only your shields. But your shield upgrades are useless as well. Very big investment.

Protoss vs Zerg - Similar to the upgrades you would want facing a Terran but the opposite. Attack is very important against zergs. Higher attacks is great for stalkers kiting roaches and getting rid of pesky mutalisk early. Also shields are a great upgrade for kiting because they regenerate unlike hp and there is no risk of an EMP. Be aware of fungal growth though it is quite intense. So technically your upgrades should look like this. 1-0-1 > 2-1-2 > 3-2-3 > Max-3-Max > All Max.

Again if you have two or more bases its always your choice of how many forges you want to build and can always do a basic 1-1-1 > 2-2-2- > 3-3-3 > max-max-max concept. It all depends how confident you are in your army count and how much resources you would invest in upgraded units. But technically i would do a one forge off my main , than a second once i expand natural and pretty much follow those upgrade guidelines for a two forge build.

Five gate or four gate?

Five gate more effective than a four?

Well lets face it, a four gate technically is an all in. So.. why not make five to increase your unit count and reinforcements.

Now I know this will cause a delay in expanding in case your opponent holds it off. But if your really going for that all in win with devastating offence within a seven minute time scale. I prefer five gates over four what do y'all think?