I own the 3a sigs but listened to the 2CE extensively when I was shopping so I'm pretty familiar with it. They are good for everything although they are a bit deficient in the high end (or bottom heavy take your pick) to my ears as well as Swerd who listened with me. They create an amazing 3D soundstage (with a small sweet spot) and play plenty loud for HT if your amp is big enough. The sweet spot is small about two human heads close together. If you plan on having people sit well of axis the soundstage suffers. Depending upon the size of the room 100 to 200 wpc will be plenty to sustain 100 dB. I went up to the 3a because of the high frequency improvement.
Now that was 2003. If I were in the 2 CE price range today I would go another direction. I would suggest you try to listen to the Salk Song towers or the Philharmonic speakers of Dennis Murphy. They sound great with flatter frequency response, image nearly as well with a much larger sweetspot, are similarly efficient and look better. I know Song Tower owners who are usually happy to permit auditions as well as Dennis Murphy who lives nearby. PM me if you are interested and near Maryland.