What is the best digital SLR camera or Interchangeable lens camera?

The one that feels right in your hands. Work out a budget and find a dealer who'll let you handle a couple of candidates.

The dSLR also is an interchangeable lens camera. The best dSLR is the Hasselblad H4D-60. All dSLR's are basically the same no matter what brand or model. MILC's, EVIL's, and SLT's all have interchangeable lens systems but are more varied in properties. I'd still prefer the dSLR.

ILC type cameras, the best one so far (best image sensor) is the Fuji X Pro 1. But it's 1,700 US dollars body only. With Fuji's backing, it will grow and be around, so that's not an issue. but at well over 2,000 US dollars when you throw in one lens, it's a bit steep, and the camera is anything but compact. The best from Sony when price is taken into account would be the NEX 5N. But know that it's due for replacement. The follow up to the NEX C3 is the NEX F3 and it should go on sale June or July, and the NEX 5N is next to be replaced. I like the NEX 7, it has more features than the other NEX bodies, and it's the only one with the amazing OLED viewfinder. I personally don't like the 24MP sensor, it's too dirty in low light. Other than that it's great and it has been a smash hit with pro and enthusiast photographers as a more compact camera to carry when the dSLR needs to stay at home. Skip the Nikon J1 and V1. They have the worst performing image sensors of all the ILC type cameras (you can check at DxOmark.com). Hopefully Nikon uses a better image sensor for the next round. Having said that, the 1 series from Nikon still crushes any compact camera. I'd take a Panasonic GF5 (in white please) over the J1 or V1. I'll skip over the Nikon and Canon dSLRs, since others will recommend them, and I'll just end up saying the same thing. Check out the Sony A57, that's the dSLR to beat this year, it's a bang for the buck model at just 699. Canon and Nikon don't have anything like it for that price, so it's worth a look. I almost forgot. check out the new Samsung NX 1000. I've decided to get that one in white because carrying my dSLR around is getting old, and I'll only use it for paid gigs once I get my Samsung. If the follow up to the NEX 5N is all around better, I'll either sell the NX1000 or just give it to a family member. http://www.imaging-resource.com/PRODS/samsung-nx1000/samsung-nx1000A.HTM