I think a lot will depend on what you have. If your cards are high value (e.g., > $1000), then I would sell through an auction house like those mentioned before (REA, Goodwin, etc.) I send my better cards to Goodwin because they have 0% seller's commission, and a closing auction policy that benefits consigners (which is all lots end at the same time). Although I've never used them, B&L can be good also since they have one of the lowest buyer's premiums and an even better closing auction policy for consigners. (You don't even have to bid on an item before extended period starts.) If you have a bunch of cards, high and low value that you don't really want to deal with, you might try an auction house that caters to all types of buyers (high and low items) like Huggins and Scott. Again, I've never consigned with them, but I believe they will sort your items into different lots for you to maximize value. For example, they might put a bunch of your lower value cards in a 1910-30s lot, and highlight higher value cards singly in their own lot. If you just have a bunch of lower to medium value cards (under $300), I would just slowly ebay the cards individually.
One more word of caution. Do not be conned by expiring best offers if you're uncertain about the value of your card. Let your auction items run. For example, if someone says I'll offer $500 for this card or $2000 for everything because your cards are worth this because of bleh, bleh, bleh, you need to make sure that other people know this card (or everything is for sale), so that others can put in their offers. If no one else offers that can beat that price, take it, but make sure others have a chance to "bid." When selling items on ebay, I've had a lot of people message me with lowball offers, and if I didn't know better, I might've taken them. More often than not, these cards ended up selling for far more than I was offered.
Finally, you might post a few of cards here. If you have some rare ones, it can cause a feeding frenzy on this board. I know that I've seen some finds, and have instantly messaged the poster asking when he was going to sell his cards and where.
Good luck!