see depends what you want, as average player no matter is it rybka, hydra, fritz...not about version, i sometime still use fritz 6 and still is good enough to analyze (i used to say if someone called G Kasparov could prepare himself with Fritz 5 with some weak Pentium in end of 90's, then what s wrong with my fritz6 at even much powerful computer)
well lets stay on fritz or chessbase, these programs are tools, powerful and very practical for use, with huge databases where you can search positions, openings, endgames - everything. i think chessbase gives annotations with arrows, for trial you can download from chessbase.com, either fritz demo or chessbaselight. and they are very good for analyze, particularly tactical possibilities.
for training, more precize, for playing training games i can recomend chessmaster (or something similar if there is ), i used to play at old CM's now I still sometime use CM10th edition, and this program is not tool, managing with databases or opening trees is very hard and unpractical, but playing against it's ratings is extreme pleasure, due to - various styles. all these you can adjust in fritz but i still find it to crude for playing any training games against it.
naturally it is best way to play against humans, but if you play against computer program you'll improve yourself in many ways, but the most is to realize importance of every move and position which can arise, because - silicon monster does not forgive!
It appears that there are number of softwares avalable. Some of them free and some you pay. This Chess.com forum has many geniuses, grand masters and experienced players. I am new at this and need some advice, in buying a software, that is user friendly and quick to get started, up and running. I also believe that some softwares have training features to learn. I think the foloowing needs attention.
1. easy to use and good for all levels of players to study, learn, analyse and so on.
2. Some software, that allows annotating with colorful arrows.
3. easy for training.
I hear people talking about stockfish,rybka, chess base, houdini.
SCID seems to be great. Is there any other like SCID available ,free or to buy.
Incidentally where do you buy these.
Thanks.
Murthy