My favorite panel is the 3D Fish, which looks a lot like the iPhone Koi Pond app. The panel shows you the date and time, while three or four fish swim around it. The fish represent some kind of notification, depending on their color. You can download more panel themes from the Sony Ericsson Web site for free, though the options are a bit limited. The only one I saw worth downloading was the Facebook panel, which would allow you quick access to your profile and your friends.
The biggest issue I had with the X1's interface was its sluggishness - a common problem with Windows Mobile devices (although this was an improvement over vanilla Windows Mobile). Moving between panels could be slow and sometimes the touch screen wasn't as responsive as it should be. At times, it took multiple taps to get an application to open. The phone never froze up or crashed in my hands-on tests, however.
In my experience, many manufacturers that try to pack business and entertainment functions into one device often skimp in certain areas. The X1, however, is brimming with features. The X1 comes with the Microsoft Mobile Office Suite and support for Microsoft's Direct Push Technology for real-time message delivery and synchronization with your Outlook calendar via the Exchange Server. It also has support for POP3 and IMAP e-mail accounts; and it comes with a PDF reader, a notepad and a task list.
The X1 comes with Internet Explorer and Opera Mobile. You can also access Google features such as search, Gmail and Google Maps easily through the Google panel. I browsed the Web over AT&T's 3G network and via the integrated Wi-Fi and was pleased with the X1's speed over both connections. I'm not a big fan of Opera Mobile, but I found surfing the Web easy enough.
The X1's multimedia player impressed me. The touch-friendly player has a similar interface to the PlayStation and the PSP. The player is fairly basic, but has a playlist function and supports album art. I was disappointed that there was no equalizer, however. The media player supports MP3, MP4, AAC(+), WMA, WMV, MIDI, MPEG-4, WMV and many other video and music formats. It also has podcast support, an FM radio, a standard 3.5-mm headphone jack (which many handsets, like the G1, lack), and a streaming media player.