A note for the unwary.  Some guitar accessory packs include strings.  It is important to note that strings are a very personal issue for guitarists.  There is a huge range of sizes (thicknesses) and the string coatings change tone dramatically.  It is probably to safe to buy more of the type you note your guitarist regularly uses - but ensure you get the exact same string diameters.  If your guitarist is just starting out or keen to experiment this is less of an issue.

Free gifts for the guitarist iPhone / iPod

Gibson App

Guitar Rock Tour 2

Pocket guitar

Drum Kit Lite

Free gifts for the guitarist PC

Guitar tuner

Another guitar tuner

Angelfires free books and other stuff

Guitar wall papers

More guitar wallpapers

Also think about downloading some tablature of favorite songs, or chords and lyrics.  Print them out and put them in an old binder to make an almost free gift for under the Christmas tree.  Main cost is time.

I use these products and don't have many problems

Adaware - spyware buster by Lava Soft

Avast Free virus protection - this is the one I use currently - I used to use AVG below.

AVG Antivirus

AmpliTube

Paul Reed Smith Jam Amp

Intua Beatmaker - BeatMaker is a new generation of mobile instruments and music creation software. Inspired by hardware beatboxes, loop samplers and software sequencers, it combines them to turn the iPod into a unique, inspirational software instrument. Using BeatMaker creative tools, you can compose, record, arrange, and tweak live your ideas into a complete song, ready to be shared with others