Was going to post this in the apps forum but think thats just for iphone?
anybody got any good must have apps to take advantage of the android software?
My help us if we knew what you hoped to be able to do with your phone. IIRC from another thread you're coming from an iPhone so you'll be able to find Android counterparts of nearly all major apps and probably most of your others.
The real beauty of Android is the freedom and flexibility your have. You can set any app to serve as your default for a specific function, i.e. browser, music player, email, calendar, etc. A good place to start is probably the keyboard. Try the stock version on whatever device you end up with and if you don't like it, you can change it. Swype and Swiftkey are 2 of the most popular--my personal favorite is Swiftkey--predictive text is so good I can very nearly complete entire sentences just from its suggestions.
There are a bunch of good browsers--I personally stick with Chrome for the syncing across platforms/devices but also like Dolphin.
Google Play Music works great for either streaming your music library from the Google cloud (free service) or from your device.
I'm also a big fan of Nova Prime launcher--allows for a more stock appearance but also adds great features like gesture based actions, unread count badges, and use of alternate icon themes.
SwipePad provides the ability to perform actions (i.e. Home button) or launch apps by touching edges of the screen.
As far as widgets, I use BobClock, Minimalist text, Android Pro Widgets (specifically twitter and calendar), Eye in the Sky weather, and Widget Locker (for alternate unlock sliders and lockscreen widgets). I like Android Pro Widgets because they allow for various themes and the ability to adjust the transparency of the background--like my wallpaper to be consistent across the screen. I use Widget Locker to replace the default lock screen with the Jellybean slider with the ability to quick launch apps from the slider.
I've also used Airdroid and iSyncr to move files from computer to device but found I prefer the simplicity of Android File Transfer on my Mac--plug in and just drag and drop.