+1I would personally go with an oil pressure gauge over an oil temperature gauge if you had to choose between the two. Only rationale being that the biggest disaster for oil in a motor would be a loss of oil. An oil pressure gauge would give you a fairly good indication that this is occurring. Obviously oil can be too hot or cold, but on a daily driving vehicle neither condition is likely to cause a failed engine. Just use a common sense rule of thumb and wait for the engine to warm up before you pound on it. Just my opinion though, lots of people go with an oil temp gauge (heck, I don't have oil temp or oil pressure!).