[HD2 General] friend'scatdied:
APN via going to Settings -> Menu -> All Settings -> Connections -> Connections -> Advanced -> Select Networks -> Edit -> My ISP (set everything manually).

These are the tweaks I use:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\Comm\BCMSDDHD1\Parms]
"11nModeDisable"=dword:00000000

[HKEY_LOCAL_MACHINE\Comm\ConnMgr\Planner\Settings]
"CacheTime"=dword:00000014
"SuspendResume"=hex(7):\
47,00,50,00,52,00,53,00,5f,00,62,00,79,00,65,00,5f,00,69,00,66,00,5f,00,64,\
00,65,00,76,00,69,00,63,00,65,00,5f,00,6f,00,66,00,66,00,00,00,00,00
"VPNCacheTime"=dword:00000014

[HKEY_LOCAL_MACHINE\System\StorageManager\FATFS]
"CacheSize"=dword:00010000
"EnableCache"=dword:00000001

[HKEY_LOCAL_MACHINE\System\GDI\GLYPHCACHE]
"limit"=dword:00080000
"limit0"=dword:00080000

[HKEY_LOCAL_MACHINE\System\StorageManager\Filters\fsreplxfilt]
"ReplStoreCacheSize"=dword:00020000

[HKEY_LOCAL_MACHINE\Drivers\Display]
"VMMaxHeapSize"=dword:02000000

[HKEY_LOCAL_MACHINE\Drivers\Display\Settings]
"SMI2 AllocSizeMB"=dword:00000020

[HKEY_LOCAL_MACHINE\Software\HTC\HTCMenus]
"EnableVSync"=dword:00000000

[HKEY_LOCAL_MACHINE\Software\HTC]
"MemoryRequired_ByAP"=dword:00080000

[HKEY_LOCAL_MACHINE\Software\HTC\HTCAlbum]
"require_activate_memory"=dword:00005000

[HKEY_LOCAL_MACHINE\System\GDI\Drivers]
"Bpp"=dword:00000018

[HKEY_LOCAL_MACHINE\Software\HTC\HTCScroll]
"dist_to_pan"=dword:00000014
"flickdown_threshold"=dword:000007d0
"flickup_threshold"=dword:000007d0
"friction"=dword:0000000e
"init_time_period"=dword:00000001
"velocity_factor"=dword:00004650

[HKEY_LOCAL_MACHINE\Software\HTC\TouchGL]
"FilterPixelRange"=dword:0000001e
"FlickGestureDistance"=dword:0000000a
"GestureEnable"=dword:00000032
"PinchDistance"=dword:00000032

[HKEY_LOCAL_MACHINE\Software\Opera\Info]
"az_overview_threshold"=dword:00000020
"EnableVisualBack"=dword:00000001
"fontcachesize"=dword:00000100
"PanFps"=dword:00000032
"ZoomFps"=dword:00000032

[HKEY_LOCAL_MACHINE\Software\Opera\Prefs\User Prefs]
"History Thumbnail Size"=dword:00000200
"Home URL"="http://www.google.com"
"Maximum Allowed Tabs"=dword:00000009

[HKEY_LOCAL_MACHINE\Software\Opera\Defaults]
"VibrationEnabled"=dword:00000000
"ZoomSliderEnabled"=dword:00000001

[HKEY_LOCAL_MACHINE\Software\HTC\TextSelection]
"EnableMagnifier"=dword:00000001

[HKEY_LOCAL_MACHINE\Software\HTC\Camera\Image\JpegQuality]
"SuperFine"=dword:00746028

[HKEY_LOCAL_MACHINE\Software\HTC\AudioManager_Eng\Config]
"enter_suspend"=dword:00000000

[HKEY_LOCAL_MACHINE\Software\HTC\Manila]
"HomeLSKPath"="!\"\\Windows\\manila.exe\" --switchtopage Manila://people\\browserlayer\\?.page"
"HomeLSKText"="Contacts"
"HTCScroll.Enable"=dword:00000001

[HKEY_LOCAL_MACHINE\Software\Opera\MemoryLimits]
"AllocLimit"=dword:04300000
"HeapLimit"=dword:04600000
"memory_heap_threshold_size"=dword:00020000
"mmap_reserve_size"=dword:01400000
"sbrk_reserve_size"=dword:02f00000

[HKEY_LOCAL_MACHINE\Software\HTC\YouTube]
"TextScale"=dword:00000032

[HKEY_LOCAL_MACHINE\Software\HTC\Calculator]
"Vibrate"=dword:00000000
"VibrateLevel"=dword:00000000

[HKEY_LOCAL_MACHINE\Software\HTC\StreamingDShow]
"EnableRotateScreen"=dword:00000001

[HKEY_LOCAL_MACHINE\Software\HTC\YouTube]
"EnableRotate"=dword:00000001

[HKEY_LOCAL_MACHINE\Software\Jataayu\Messaging]
"MaxRecipients"=dword:00000032

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings]
"MaxConnectionsPerServer"=dword:0000000a

[HKEY_CURRENT_USER\Software\HTC\Manila]
"Weather.EnableCurrentLocation"=dword:00000000

[HKEY_CURRENT_USER\ControlPanel\Notifications\{A877D65B-239C-47a7-9304-0D347F580408}]
"AvailableOptions"=dword:0000000f

[HKEY_CURRENT_USER\ControlPanel\Notifications\{A877D660-239C-47a7-9304-0D347F580408}]
"AvailableOptions"=dword:0000000f

[HKEY_CURRENT_USER\ControlPanel\Notifications\{A877D661-239C-47a7-9304-0D347F580408}]
"AvailableOptions"=dword:0000000f

[HKEY_CURRENT_USER\ControlPanel\Keybd]
"InitialDelay"=dword:00000064

[HKEY_CURRENT_USER\Software\HTC\Manila]
"LSK_Send_Msg"=dword:00000000

[HKEY_CURRENT_USER\Software\Microsoft\Inbox\Settings]
"ShowReplyAllEmailSK1"=dword:00000000

[HKEY_CURRENT_USER\Software\Adobe\AdobeReaderLE.25]
"EnableReflow"=dword:00000000
"InitialZoomType"=dword:00000001

[HKEY_CURRENT_USER\ControlPanel\Volume]
"Mute"=dword:00000001

Many of them are pulled from the threads pinned in this forum and are used solely to improve performance (credits to cgrec92, g.lewarne, Sean3, tboy2000). There are a number in there that speed up the connection however and the disabling of My Location and setting of auto-disconnect might be key.

Also of important note is that I use Windows Live Push mail. The consequence of this is that my data connection is always open and I suffer from subpar battery life. Not sure if the registry tweaks for connection would have any effect on those not using push e-mail.

Due to the nature of the comprehensive tweaks (i.e. I designed this cab for my personal use) it is for 576MB and TMOUS compatible ROMs only.