Welcome to the forums, Broadwille. ; A little more detailed info might help hone down the recommendations - what types of shooting do you intend to do (portraits, landscape, wildlife, scenic, travel, architecture, sports), what types of conditions (day, night, cloudy, indoors, outdoors)...what type of camera do you have now, and what if anything do you feel it's missing?
Just to clarify on one thing: the NEX cameras aren't technically 'DSLRs'. ; They have DSLR-type APS-C sensors in them, and can take equally good shots, but are different in the way they work - there's no mirror at all, they don't have a phase-detect focus system, and have no viewfinders. ; They function very closely to the way a P&S camera might, in that you hold them up viewing the LCD screen, line up the shot and settings, then take the photo. ; They have a big advantage over DSLRs in portability, but tend to be not quite as fast to shoot or focus, and won't be as usable for extreme photogaphy like long-lens wildlife shooting or action sports.
As for the main differences - there are two Sony NEX cameras currently - the NEX3 and the NEX5. ; The last letter, the 'K' and 'A' and such indicate the lens packages and body colors that you choose. ; Because these are interchangeable lens cameras, they can be bought as just a camera body, with the lens to be chosen later by you, they can be bought with the 16mm fixed lens in the box, they can be bought with the stabilized 18-55mm lens in the box, or they can be bought with BOTH of these lenses in the box. ; For general photography purposes, the 18-55mm lens is a little larger, but much more useful, since you have some zoom ability.
The main difference between the NEX3 and NEX5 are that the NEX3 has a slimmer body that's slightly taller, with a narrower grip, 720P HD video, and a plastic outer body shell. ; The NEX5 adds a thicker grip, a full magnesium alloy body, 1080p HD video, and a remote shutter release. ; Otherwise, they're the same sensor and take the same lenses, so the images that come out won't be any different.
Give us some info on the types of photography you do, and what you think you need in a camera - there are other options too besides the NEX, with Sony making SLT cameras (fixed mirror SLRs) and traditional DSLRs, alongside other brand offerings from Canon, Nikon, Pentax, Olympus, and Pentax, which are also worth consideration depending on your needs. ; BTW, I have a NEX3 with the 18-55mm lens that I just bought last week as a second camera to go with my DSLR, so I do know a fair bit about the camera if you need more info!