There are many things to consider. One is the image response. The usual rule of thumb is to make the IF be above 10% of the RF frequency. This can be made lower if your filtering in the RF has many poles.
Another thing is the IMD products which fall in the IF range. Pay special attention to input frequency ranges with high power broadcast stations and their harmonics.
Opps! Actually I'm quite new in this RF technology. IMD Products?? What does it mean? Is it Inter-Metal Dielectric?, in-mold decals?, intermodulation distortion?, Initial Marching Direction?, :?:
IMD products are the Intermodulation Product, which is defined as the weighted summation or subtraction of the input LO and RF frequencies. This phenomenon is due to the nonlinearity of the circuitry it self.