I agree with the YouTube statement, tons of great review and comparison videos out there.
The built in browser is pretty good, I have not found the need to replace it yet.
I didn't like the rather bland text messaging app and switched to Handcent SMS, great app, with tons of customization features to make it look they way you want it to. There are also a bunch of free themes available for it in the market, and its' free.
I use Widget Locker to replace the rather boring lock screen that comes with the phone, It costs some money (3 or 4 bucks), but if you like to tinker, it's well worth it. You can put as many sliders as you want on your lockscreen, add widgets, clutter it all up or make it clean, the choice is yours. I personally use the ICS lockscreen option with it and have 4 shortcuts straight to the phone app, handcent SMS, the camera, and basic unlock. Very clean, very useful. Go Locker is a free alternative, but if I am not mistaken it has to be used with Go Launcher, a program that also is highly customizable and replaces the main functions of Touchwhiz.
Swiftkey X for the keyboard. Unfortunately you missed the 10 cent sale, but I find this keyboard to be worth every dollar it costs. It learns the way you type and predicts your next word to the point that it is almost spooky. It also has different themes, multiple language support (I can type one word in english and the next in german and it knows the difference, no need to switch first for it to know which language you type in), and is also very customizable in the way it uses word prediction and automatic completion. Want cursor keys to be able to edit your text better? that's included as well.
ADW Launcher EX. Great replacement for Touchwhiz. Highly customizable. It will take you hours to go through all the settings, but you will be able to set up your phone exactly as you like. The amount of adjustments you can make is almost mind boggeling. No need for a tutorial, it's simple enough and the changes you make are applied immidiately, it's just a matter of going through all the menus and playing with it. Lots of premade free themes are also available.
If you have Facebook, don't let it sync your contacts, let the Samsung Social hub with facebook do that. This way you get higher quality caller id pictures. Also, as stated above, be sure to sync all your contacts with Gmail. Hopefully you can export your current contact list from the Blackberry desktop software into a CSV file and from there import them to Gmail into your computer. Use this time to clean things up a bit, and as soon as you log in with your gmail account on your phone, everybody will be there. Whem merging/joining contacts between Gmail and Facebook, sometimes it doesn't find a match for certain people, but you have the option to do the matching manually.
As for games....there are lots. Some of my favorites:
Air Attach HD
All 3 Angry Birds
Asphalt 6 HD
Bejeweled 2
Blood and Glory
Doodle Fit
Emissary of War
Fieldrunners
Flight Control
Fruit Ninja
Great Little War Game
Guerilla Bob
Hex Defense
Jelly Defense
Jenga
Labyrinth
Minecraft
Mini Squadron
NFS Shift
Peggle
Pinball Ride
Plants vs Zombies (has crashing issues)
Reckless Getaway
Reckless Racing
Samurai II Vengeance
Shadowgun (Oh yeah...like Gears of War)
Sprinkle
Tetris (crashing issues)
Trial X
Warheads
Word with Friends
World of Goo
Just to name a few...and yes...all that is installed on my phone.
That's the basics, hope it helps.
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