Microsoft recommends 512 MB. For most uses, you will want 1 to 2 GB.
Officially, Windows Vista needs a minimum of 512 MB of RAM, and 1 GB or more is recommended. Unofficially, people have run Vista on as little as 192 MB of RAM, although this performed too poorly to be of any actual use.
Windows Vista will run on a computer with a minimum of 512 MB of RAM
Barely. Vista Home Basic will run, slowly, on a system with 512MB RAM. Increasing RAM to 2GB is strongly recommended.
People have managed to run Vista on as little as 128 MB of RAM. However, 512 MB is the minimum recommended by Microsoft, and 1 GB is the amount most people will require to do something useful.
1 GB recommended
The maximum amount of RAM supported by Vista is 128 Gb (Ultimate, Enterprise and Business).
512 to 1gb ram are recommended
This depends entirely on what your computer is going to be doing and what programs it will be running. Some versions of Linux can run on just a few megabytes of RAM. On the other end of the spectrum, Windows Vista requires about a gigabyte of RAM just to have decent performance. Of course, then there are servers which will have as much RAM as the motherboard can hold.
The maximum RAM that Windows Vista Ultimate can recognise is 4GB, as long as you have the 32-bit edition. If a 64-bit edition is being run then up to 12 GB RAM can be supported.
256 should do it.
Go no less than 1gb for vista.
Most recent PC video games will have their Minimum System Requirements displayed on the packaging it came in. Refer to this chart to see how much RAM is recommended for your games. If you can not find the Minimum System Requirements, I would recommend two 2GB sticks of RAM, for 4GB total. The price for a "Dual Channel Kit" with 4GB of RAM total is relatively low compared to 8GB Dual Channel Kits and not much more expensive than 2GB Dual Channel Kits.