I created a custom content type and list definition, after upgrading my sharepoint solution I could see the list and content types under the new menu but when creating a new item, the fields were missing from NewForm.aspx
I discovered that it was due to the ContentType definition not having the FieldRefs tag, my content type was defined like this:-
<ContentType ID="0x01001376F571B0DB9D4E9384D2927DC110CF02" Name="News Article" Group="Vodafone LCD Content Types" Version="0">
</ContentType>
When it should have been like this:-
<ContentType ID="0x01001376F571B0DB9D4E9384D2927DC110CF02" Name="News Article" Group="Vodafone LCD Content Types" Version="0">
<FieldRefs>
</FieldRefs>
</ContentType>