cwendy41: "What Android tablets are there out there (or about to come on the market) that don't require data plans and will run on wifi? I was thinking about getting one but was told most of them require a data plan. I have also not researched this much, since I already have an iPad."
Okay, i am not an expert on this subject, but here is what i've gleaned from various sources. (And to the best of my knowledge, all of these are available without any kind of cellular contract, in fact for most of them a cellular contract isn't even possible.)
If you want to try out a different size from the iPad the Nexus 7 is almost definitely the way to go. The cons are lack of an SD card slot, and for some but obviously not all people, the lack of cellular wireless and a rear facing camera. The pros are even with those lacks you can not get better hardware in that size for that price ($200 for 8GB and $250 for 16GB) It's got a quad core processor and a 1280 x 800 resolution that blows the Kindle Fire and Nook Tablet out of the water (those being the only other two good tablets for around that price.) And that of course is before you get to the fact that it's going to ship (in about two weeks) with Android 4.1, while the Kindle and Nook have a horribly mangled form of Android 2.3. The Nook Tablet was a great deal at the time i got it about nine months ago (and still is pretty good if all you want to do is read books and watch TV and movies, either by ripping the files yourself or via Netflix and Hulu Plus) but it's totally outclassed now.
In terms of the size itself, based on my experience with the Nook Tablet, 7" is a pretty good compromise between usability and portability. It's much easier to see and use than a cell phone screen. I'm pretty sure it will fit well in even a moderately small sized purse, it certainly rattles around inside my messenger bag with tons of room to spare, and if you've got cargo pants you can actually just stick it in your pocket. I've been very happy to be able to take my Nook Tablet with me without actually carrying anything just by wearing the right set of pants or shorts.
In the mid range in terms of size the Samsung Galaxy Tab 8.9 and the Sony Tablet S are both supposed to be very good.
If you want a "full size" Android tablet there are two lines you probably ought to be looking at, the Samsung Galaxy Tab 10.1, and the Asus Transformer Line.
The Samsung Galaxy Tab 10.1 is the one that Apple recently got an injunction against, cause they're jerks, but they're also a little behind the times because it seems the Galaxy Tab 2 10.1 is out now and still available. It's supposedly very good and one of the best selling tablets out there aside form the iPad (which is probably why Apple is going after them so hard.)
Personally though if i were going to get a full sized tablet i would get one of the Transformers.
The original Transformer got a lot of attention because it was a pretty good tablet and had an optional keyboard attachment. I believe the keyboards generally run between $100 and $150, but along with the keyboard they have a trackpad, an extra full size USB port, an SD card slot, and an extra battery that extends the the runtime by an extra three or four hours.
The Transformer Prime (TF201) was the second iteration on the design, and probably the bare minimum model you ought to consider since it was one of the first tablets to come with a quad core processor.
Shortly after the Prime they released the Transformer Pad TF300T, which was very similar to the Prime, but used a slightly slower processor (still quad core though) and slightly cheaper materials, particularly a plastic body instead of an aluminum one. This means that it's a fair bit cheaper than the Prime, and as an added bonus it ships with Android 4.0 instead of requiring an over the air update like the Prime.
Then more recently they announced the Transformer Prime Infinity, which is due out in about two weeks. It has an improved screen, 1920×1200 vs 1200x800, putting it in the top tier of tablet resolutions and almost equal to the iPad 3. (Also note, that means the Nexus 7 currently has the same resolution in 7 inches as most top tier 10 inch tablets had just six months ago =) It also fixes some issues with GPS reception that the original Prime reportedly had. (Which i believe the TF300 avoided by means of the plastic shell.)
Another benefit of all the Transformers is that that Asus traditionally does very light skinning of the Android OS. If you're not aware, a lot of manufactures develop their own "skins" that go on top of the base Android UI. This is supposed to make each manufacturer's version of the OS look distinct from the others. Occasionally they come up with some neat features to add, but mostly IMHO they just muck things up. A lot of Android fans prefer the "pure" experience, which you generally get by either buying a Nexus device straight from Google or rooting the device. However from what i've told Asus comes pretty darn close to "pure" Android on its own.
Of course when the Infinity comes out the Prime and the TF300 will probably get price drops, making them still viable choices. Also meaning of course whatever you want to get you probably ought to wait about two weeks until the Nexus 7 and the Transformer Infinity come out and the market has had a chance to respond.
So if you want to do some more research on your own, here are some of the links i looked at:
Wikipedia's Comparison of tablet computers
CNET: Best Android tablets
TechRadar: 10 best tablet PCs in the world today
TechRadar: 15 best Android tablets in the world
Engadget: Nexus 7 review: the best $200 tablet you can buy
A Look at the Hardware Inside Google's Nexus 7 Tablet
If you want a few really technical details, especially if you follow the link to the original iFixit post.
And finally: Google Nexus 7 Review: 'Its Mission Is To Go Out And Kill Rogue Tablets'
I love the extension of the Blade Runner metaphor in this one :)