The problem is running it 24x7, then a small 50w is still 438 Kwh each year. That's more than a 10% increase in yearly use for a typical two person household...
For me that would be a $49 cost per year, or a cost of little over $4 per month.
My workstation bursts to 600w+ for 15-20 minutes at a time when compiling, for comparison.
If so, you should get a LED alternative.