I assume you mean that you're also removing the pink crap that comes on the default heatsink under the tape?
Most HSF's come with some phase change compound already applied to the heatsink surface, and it is protected by some tape. Unless you do some aggressive overclocking, that compound will work fine. No need for additional Arctic Silver.
But: If there's no compound, just bare metal, you absolutely MUST apply some Arctic Silver or something similar. The goop is to fill in the micro pockets in the surface. No matter how smooth it seems, those gaps are still there and must be filled in. Otherwise the CPU overheats.