I would suggest Unity myself. Both are actually fairly comparable, however I feel that Unity is more Indie friendly. It supports more scripting languages to create your logic in, the asset store has many inexpensive ready to use models (when the time comes) and the free license contains everything you will need to release a PC game for profit. UDK is a bit more powerful and contains some features that you do not get with Unity. Unity's Pro license is VERY close to the UDK system but much cheaper. Although the numbers have changed and I hear UDK now offers a royalty based full license the following journal entry of mine explains in more detail why you may wish to avoid UDK.
Daz3D models are also ready to go and fully supported in Unity which to me is a major benefit. Daz3D is different modelling program that allows you to focus more on assets, clothing and such instead of the actual modeling process, for those of us non artistic types it's a means of actually being able to create usable 3D models and characters with animations.
Do keep in mind that these are my opinions and suggestions but there are many other methods, engines and tools that you can use. Many have their own benefits and draw backs, Unity is no exception, I'm sure there are down sides to using it although none that have ever effected me personally. I would be interested in discussing all of this in a bit more detail if you would like. You can find my contact details in my Game Dev profile and also on my Gravatar profile linked below.
Edit / PS
Unreal and UDK are not used as much as many people may imagine an normally only by very large game studios that are not likely to hire or even talk to indie developers. The companies that can afford and have the necessity for UDK / Unreal engines normally only entertain resume's and applications from veteran game designers that come from official studios with numerous released titles under their belts. Unity is used by quite a few indie teams as well as many small and medium sized studios. As with any field there's never a guarantee but Unity certainly opens more feasibly reachable doors.