There are very few reasons to abandon a large quantity of CDs. The same is true if you already have a lot of vinyl and few CDs. Buying a CD player is probably not the best choice right now. However, don't let this isolate you from the other in the future. There is always room for a DJ who can work with both mediums.
Some styles are easier to get on one medium than another.
This is especially true of underground dance music. If you find yourself spinning a lot of rave oriented material, you may have to move to vinyl simply because most new releases come out on vinyl first. Every style has their own preference of medium. Choose the one that best suits what you want to do. This ties in very closely with style.