EBay: Smart to bid now or later?

'Nother eBay question. There's an item I've found that hasn't had any bids on it yet, yet it's been up for a few days. I really want it, but I don't know if I should bid now or wait until the end. I'm afraid that if I bid now, the next bidder will know that there's another bidder so they'll attempt to outbid me. At the same time, I'm terrified the seller will take the item down once nobody bids on it. What should I do? Is it even possible for the seller to take the item down? Thanks in advance.