Well, I transferred my data.ext4.tar file to my Linux laptop and extracted the files so I could more easily review them. Here's the biggest files on my device:
What's interesting that I found and that quickmustang might look for is the internet cache and the email cache and downloads take up quick a bit of space. Obviously your apps and dalvik-cache can also consume quite a bit of space.
There's got to be something very large that the OP has downloaded or received, etc. that accounts for the /data partition being so large.
Code:
# [COLOR="red"][B]find . -size +3500000c -ls | sed 's/^[ ]*//g' | cut -d ' ' -f 3-[/B][/COLOR]
-rw------- 1 scaryalien scaryalien 4202496 Dec 31 06:05 ./data/stericson.busybox/cache/webviewCacheChromium/data_3
-rwxr-xr-x 1 scaryalien scaryalien 7855844 Oct 30 2009 ./data/com.adobe.flashplayer/lib/libflashplayer.so
-rw------- 1 scaryalien scaryalien 4202496 Jan 1 20:02 ./data/com.weather.Weather/cache/webviewCacheChromium/data_3
-rwxr-xr-x 1 scaryalien scaryalien 15817584 Jan 15 2012 ./data/com.adobe.air/lib/libCore.so
-rwxr-xr-x 1 scaryalien scaryalien 4210721 Feb 6 2012 ./data/com.amazon.kindle/lib/libKRF.so
-rw------- 1 scaryalien scaryalien 4202496 Dec 20 13:44 ./data/com.amazon.kindle/cache/webviewCacheChromium/data_3
-rwxr-xr-x 1 scaryalien scaryalien 16570800 Jan 19 2012 ./data/com.google.earth/lib/libearthmobile.so
-rw-r----- 1 scaryalien scaryalien 3862528 Jan 11 11:56 ./data/com.google.android.gm/databases/mailstore.scary.alien@gmail.com.db
-rw------- 1 scaryalien scaryalien 4202496 Jan 11 11:56 ./data/com.google.android.gm/cache/webviewCacheChromium/data_3
-rw------- 1 scaryalien scaryalien 4202496 Jan 7 15:29 ./data/com.google.android.browser/cache/webviewCacheChromium/data_3
-rw-r--r-- 1 scaryalien scaryalien 7392949 Jan 11 05:04 ./data/com.android.providers.downloads/cache/downloadfile-1.apk
-rw------- 1 scaryalien scaryalien 4202496 Jan 7 04:30 ./data/com.metago.astro/cache/webviewCacheChromium/data_3
-rw-r--r-- 1 scaryalien scaryalien 4732928 Dec 7 15:30 ./dalvik-cache/system@app@Maps.apk@classes.dex
-rw-r--r-- 1 scaryalien scaryalien 11324176 Dec 7 15:30 ./dalvik-cache/system@app@Thinkfree.apk@classes.dex
-rw-r--r-- 1 scaryalien scaryalien 5019496 Jan 11 05:04 ./dalvik-cache/data@app@com.google.android.apps.maps-2.apk@classes.dex
-rw-r--r-- 1 scaryalien scaryalien 4707663 Dec 19 05:15 ./app/com.adobe.flashplayer-1.apk
-rw-r--r-- 1 scaryalien scaryalien 5240716 Dec 19 05:09 ./app/com.google.android.music-1.apk
-rw-r--r-- 1 scaryalien scaryalien 8634759 Jan 4 16:15 ./app/com.google.earth-1.apk
-rw-r--r-- 1 scaryalien scaryalien 7392949 Jan 11 05:04 ./app/com.google.android.apps.maps-2.apk
-rw-r--r-- 1 scaryalien scaryalien 5735832 Jan 6 16:46 ./app/stericson.busybox-1.apk
-rw-r--r-- 1 scaryalien scaryalien 3708455 Dec 22 06:32 ./app/com.android.vending-1.apk
-rw-r--r-- 1 scaryalien scaryalien 3511811 Jan 9 03:33 ./app/com.keramidas.TitaniumBackup-1.apk
-rw-r--r-- 1 scaryalien scaryalien 8781135 Dec 21 07:10 ./app/com.adobe.air-2.apk
-rw-r--r-- 1 scaryalien scaryalien 9587332 Jan 11 05:02 ./app/com.amazon.kindle-2.apk
What's interesting that I found and that quickmustang might look for is the internet cache and the email cache and downloads take up quick a bit of space. Obviously your apps and dalvik-cache can also consume quite a bit of space.
There's got to be something very large that the OP has downloaded or received, etc. that accounts for the /data partition being so large.
.